Remove platform tenancy from SXCHNGE customer BFF (#34)

.agents/skills/review-backend-change/SKILL.md

@@ -0,0 +1,59 @@
+---
+name: review-backend-change
+description: Review, fix, and validate the complete SXCHNGE backend contribution for a task. Use before reporting completion whenever Go, protobuf, or other backend code under backend/ was added or modified, or when the user requests a backend implementation review.
+---
+
+# Review Backend Change
+
+## Establish the review scope
+
+1. Read the repository root `AGENTS.md` and `backend/AGENTS.md` completely.
+2. Inspect repository status and the full backend diff attributable to the
+   current task, including uncommitted and committed changes against the task's
+   base.
+3. Separate unrelated pre-existing work from the task contribution. Preserve
+   it and do not include it in review fixes.
+4. Identify changed behavior, public or internal contracts, and expected test
+   coverage before judging individual lines.
+
+## Review and fix the contribution
+
+1. Apply every quality requirement in `backend/AGENTS.md` to the entire task diff,
+   not only the most recently edited file.
+2. Search the repository for canonical protobuf messages, enums, Go types,
+   interfaces, and shared domain definitions before accepting new ones.
+3. Check project-error usage, cause preservation, cohesion, naming, API and
+   module boundaries, duplication, dead code, and testability.
+4. Review structured logging at meaningful operational and domain boundaries.
+   Check level selection, context, sensitive-data handling, and duplicate error
+   logging.
+5. Review success, edge, and failure paths. Add or update focused tests for the
+   changed behavior.
+6. Fix every in-scope issue found, then re-read the resulting complete backend
+   diff. Repeat until no task-caused finding remains.
+
+Do not weaken checks, suppress failures, or modify unrelated user work to make
+validation pass.
+
+## Validate
+
+After review fixes are complete, run these commands from the repository root:
+
+```text
+make test
+make lint-backend
+```
+
+Then select and run every applicable security command from the change-scoped
+security completion requirements in the root `AGENTS.md`.
+
+All commands must succeed before reporting the backend task as complete. If a
+command fails, determine whether the task caused it and fix in-scope failures.
+Report an external or environmental blocker with the exact command and failure;
+never represent blocked validation as successful.
+
+## Report the result
+
+Summarize the reviewed backend scope, material fixes made during review, tests
+added or updated, and the outcome of each required command. Call out contract,
+migration, rollout, security, or observability implications that remain relevant.

.gitignore

@@ -25,3 +25,7 @@ pnpm-debug.log*
 
 # Local editor configuration
 /.vscode/
+
+# Local BFF configuration and build output
+/backend/config.yml
+/backend/bff

AGENTS.md

@@ -74,8 +74,8 @@ repository changes do not require a branch.
 
 ## Scoped implementation requirements
 
-- For backend code under `api/`, read and follow
-  [`api/AGENTS.md`](api/AGENTS.md). Before reporting completion, use the
+- For backend code under `backend/`, read and follow
+  [`backend/AGENTS.md`](backend/AGENTS.md). Before reporting completion, use the
   [`$review-backend-change`](.agents/skills/review-backend-change/SKILL.md)
   skill.
 - For Dart or Flutter code under `frontend/`, read and follow

Makefile

@@ -1,3 +1,7 @@
+.PHONY: test
+
+test: test-backend test-frontend
+
 .PHONY: test-frontend
 
 test-frontend:
@@ -8,3 +12,16 @@ test-frontend:
 	cd frontend/packages/sxchnge_theme && flutter test
 	cd frontend/packages/sxchnge_theme/example && flutter test
 	cd frontend/app && flutter test
+
+.PHONY: test-backend lint-backend run-backend
+
+test-backend:
+	cd backend && go test -race ./...
+
+lint-backend:
+	cd backend && go test ./internal/architecture
+	cd backend && test -z "$$(gofmt -l .)"
+	cd backend && go vet ./...
+
+run-backend:
+	cd backend && go run ./cmd/bff

README.md

@@ -1,7 +1,7 @@
 # SXCHNGE
 
 Product repository for the sxchnge public website, Flutter consumer app, reusable
-packages, and planned backend for frontend (BFF).
+packages, and a backend for frontend (BFF) bootstrapped from Sendico.
 
 ## Current state
 
@@ -11,8 +11,9 @@ with `go_router`. Its interface uses the shared theme's colors and typography.
 
 **Authentication, email verification and analytics use dummy services.** No real
 account or session is created, no email is delivered, and no analytics data is
-transmitted. The backend is documentation only. Session/KYC access guards and
-Sendico integration are not implemented.
+transmitted by those app services. The backend now contains locally owned copies
+of Sendico’s BFF runtime, auth/session stack and account service. The app is not
+connected to that backend or to Sendico yet.
 
 ## Repository structure
 
@@ -23,7 +24,7 @@ Sendico integration are not implemented.
 | [`sxchnge_theme`](frontend/packages/sxchnge_theme/README.md) | Reusable light/dark themes and bundled Onest font |
 | [`sxchnge_auth`](frontend/packages/sxchnge_auth/README.md) | Shared auth contracts, providers, two-factor page and dummy services |
 | [`sxchnge_analytics`](frontend/packages/sxchnge_analytics/README.md) | Typed journey events, recorder and bounded in-memory dummy analytics |
-| [`backend/`](backend/README.md) | Planned BFF and Sendico integration boundaries |
+| [`backend/`](backend/README.md) | Copied BFF/auth/account foundation and isolated public Sendico contracts |
 | [`.agents/skills/`](.agents/skills) | Repository agent skills |
 | [`docs/`](docs/implementation.md) | Implementation records and UX measurement contracts |
 
@@ -143,18 +144,21 @@ usability, accessibility and journey measurement under the repository's UX rules
 
 ## Product boundaries
 
-The intended integration is: **consumer app → sxchnge BFF → supported Sendico API**.
+The integration is: **consumer app → sxchnge BFF → Sendico public HTTP API**.
+SXCHNGE is one organization in Sendico; its customers are owned locally.
+Local accounts have no organization tenancy, membership, roles or policy engine.
 
 - sxchnge will own consumer registration/sessions, onboarding and exchange UX,
-  and mappings to stable, organization-scoped Sendico customer references.
+  and mappings from local customers to organization-scoped platform resources.
 - Sendico remains authoritative for payment execution, KYC records and
   verification, policy decisions and limit enforcement.
 - The sxchnge organization, backend integration principal and individual customer
   references are distinct identities. Consumers must not share the integration
   account's customer identity.
-- The BFF should use a supported API contract rather than copying Sendico's BFF
-  or depending on its local internal modules. Integration credentials belong in
-  the backend.
+- The BFF uses only the public HTTP API. Existing BFF/auth/account components
+  are copied into SXCHNGE-owned code; private transports and sibling module
+  dependencies are not used.
+  Integration credentials belong in the backend.
 
 Before backend integration, agree on the customer, KYC, eligibility/limits and
 customer-scoped payment contracts for one complete transaction flow. These are
@@ -224,3 +228,16 @@ instructions also support authenticator challenges; actual TOTP enrollment,
 validation and recovery remain backend integration work. See the
 [two-factor UX contract](docs/ux/two-factor.md) and
 [shared auth package](frontend/packages/sxchnge_auth/README.md).
+
+## Backend integration plan
+
+The [BFF architecture and Sendico service audit](docs/architecture/bff.md) defines
+consumer identity, financial-provider boundaries, reusable components, contract
+gaps and delivery phases. Selected Sendico code has been adapted with recorded
+[provenance](backend/PROVENANCE.md); the projects share no runtime modules.
+
+Run `make test-backend`, `make lint-backend` or `make run-backend` from the root.
+The copied runtime installs local authentication transport and initializes its
+account service. Signup/profile endpoints, verification delivery/completion,
+Flutter HTTP adapters and live Sendico operations remain to be wired. See the
+[backend run guide](backend/README.md) for local MongoDB configuration.

backend/AGENTS.md

@@ -0,0 +1,99 @@
+# Backend Agent Guidelines
+
+These instructions extend the repository-wide rules in the root `AGENTS.md`
+and apply whenever a task adds or modifies backend code, including Go and
+protobuf files under `backend/`.
+
+Before completing the task, review the entire backend diff produced by the
+current task, fix every in-scope issue found, and then perform the required
+validation. Use the
+[`$review-backend-change`](../.agents/skills/review-backend-change/SKILL.md)
+skill to perform this completion workflow.
+
+## Reuse existing definitions
+
+- Search the repository before introducing a protobuf message, enum, Go struct,
+  interface, or shared domain type.
+- Reuse or extend the canonical existing definition when its semantics match.
+  Do not create parallel representations or conversion layers for the same
+  concept without a clear architectural reason.
+- Avoid naming stutter in packages, types, fields, parameters, and access paths.
+  Each nested name should add meaning instead of repeating its parent context.
+  For example, prefer a concise path such as `payment.Details.ID` over
+  `payment.Payment.PaymentID`.
+
+## Use the project error model
+
+- Do not introduce `fmt.Errorf` or `errors.New`. Use the constructors and
+  wrapping helpers in `backend/pkg/merrors`.
+- Preserve the underlying cause when adding context by using an appropriate
+  `merrors` wrapping helper.
+- When no suitable project error exists, add the smallest generally useful
+  definition or helper to `backend/pkg/merrors` instead of creating an ad hoc error
+  elsewhere.
+
+## Keep modules cohesive and names concise
+
+- Review touched files for excessive size, mixed responsibilities, duplicated
+  logic, and poor separation of concerns.
+- Refactor oversized contributions into focused, cohesive files or packages.
+  Do not split code mechanically; organize it along clear domain or
+  architectural boundaries.
+- Avoid repeating directory or package context in child directory and file
+  names. For example, prefer `payment/widget.dart` over
+  `payment/payment_widget.dart`.
+
+## Review implementation quality
+
+- Review the current task's backend contribution for correctness, readability,
+  maintainability, testability, and consistency with the surrounding
+  architecture.
+- Keep public APIs and module boundaries small and intentional. Remove
+  unnecessary indirection, duplication, dead code, and speculative abstractions.
+- Add or update tests for changed behavior, edge cases, and failure paths.
+- Fix all findings caused by the current task before reporting completion.
+
+## Review logging
+
+- Ensure the contribution has sufficient structured logging at meaningful
+  operational and domain boundaries. Include useful identifiers and context,
+  but never log credentials, secrets, or sensitive payment data.
+- Follow the repository's logging style and use levels consistently:
+  - `Debug`: fine-grained runtime execution tracking useful during debugging.
+  - `Info`: important payment-domain events, module-boundary operations,
+    effective module configuration, and noteworthy but expected deviations from
+    the usual path.
+  - `Warn`: runtime errors and unexpected conditions from which the service can
+    continue or which are returned to a caller.
+  - `Error`: unrecoverable failures that cause, or imminently lead to, service
+    or component termination.
+- Avoid logging the same error repeatedly at multiple layers. Log it where the
+  layer has enough context to make the event actionable.
+
+## Required validation
+
+- From the repository root, run `make test` and `make lint-backend`, plus every
+  applicable command from the root `AGENTS.md` change-scoped security
+  requirements, after all review fixes are complete.
+- All commands must succeed before the task is reported as complete. Fix
+  failures introduced by the current task; do not silently skip, suppress, or
+  weaken checks.
+- Report the commands run and their outcomes in the final response. If an
+  external or environmental blocker prevents a command from running, report
+  the exact command, failure, and blocker explicitly; do not claim successful
+  validation.
+
+## SXCHNGE provider boundary
+
+SXCHNGE owns auth, sessions and customer management. SXCHNGE is one organization
+inside Sendico. This organization reference belongs only in the public provider
+adapter configuration. Local customers have no organizations, tenant IDs,
+membership, roles or policy engine. Do not copy platform scaffolding to satisfy
+unused dependencies; remove those dependencies from the selected components.
+Copied BFF components are locally owned and may diverge.
+Use only Sendico's public HTTP API for platform operations. Never import sibling
+Sendico modules or access its database, internal gRPC APIs, discovery or message
+bus. Keep the pinned public wire contract separate from local DTOs and models.
+Resolve the configured provider organization and customer resource ownership on
+the server. Never treat all customers as the backend integration principal.
+Use the copied structured logger, injected at operational boundaries.

backend/PROVENANCE.md

@@ -0,0 +1,62 @@
+# Copied Sendico source
+
+Source repository: `S_I/sendico` (`git.sendico.io`), revision
+`8bb20dcd622dd8eb92d289b6b34411e7eccab083`.
+
+[PROVENANCE.json](PROVENANCE.json) records each retained file, its original path
+and Git blob, and whether a Go file changed beyond namespace replacement and
+formatting. It currently covers 232 Go source/test files and 112 public OpenAPI
+files. Sources came from the pinned commit, not the dirty Sendico checkout.
+These are SXCHNGE-owned copies that may diverge independently.
+
+## Retained implementation
+
+- Chi HTTP runtime, process/version bootstrap, structured logging and health.
+- Customer password validation/hashing, account repository and account service.
+- Customer login, pending verification, session validation, refresh rotation,
+  revocation, browser cookies/CSRF and login rate limiting.
+- Verification issuance, expiry, attempts, consumption and idempotency.
+- Local Mongo connection, transactions and the repository/query implementation
+  required by account, session and verification storage, with retained tests.
+- Public OpenAPI 4.2.37 and its recursive schema references, isolated under
+  `contracts/sendico`. These wire files are unchanged except for trailing blank
+  line normalization in three YAML files; they are not local domain models.
+
+## Adaptations and exclusions
+
+Imports belong to `git.sendico.io/tech/sxchnge/bff`. The composition root selects
+local customer services. Discovery, message-bus registration, private gRPC and
+platform factories are absent. Process identity and the refresh cookie use SXCHNGE.
+Startup validates required settings and timeouts, closes failed connections and
+preserves process failures. Errors use `merrors`; logs exclude raw DB settings.
+
+The earlier extraction retained too much. Local organizations, membership,
+roles, Casbin, policies, invitations, policy seeding and their repositories and
+models are removed. There is no replacement tenant or permissive enforcer.
+Unneeded financial models/errors, ledger and wallet provisioning metadata,
+platform service names, S3 configuration and WebSocket scaffolding are removed.
+Tests specific to removed features are removed with those implementations.
+
+The copied account service now creates a local customer from a raw password,
+hashes it and commits the customer and activation token atomically. It uses the
+same configured collections as login. Deletion revokes that customer's sessions
+and deletes its record atomically; it has no sole-member rule. The copied Mongo
+transaction helper joins an active outer transaction so verification does not
+commit separately from customer creation. Generic repositories no longer expose
+organization- or permission-bound operations. Customer responses use explicit DTO fields and a mapper; they have no anonymous
+organization-account flag or embedded database record. Refresh and protected
+handlers reject inactive customers; refresh checks account-bound application
+clients.
+
+## Local additions and limits
+
+Architecture tests reject private provider imports, policy-engine dependencies
+and local tenancy declarations. Fresh Mongo replica-set tests exercise the actual
+customer lifecycle, isolation, duplicate login, rollback, deletion/session
+revocation and runtime startup without a seed. Existing retained auth/session and
+verification tests remain in place.
+
+This is a bootstrap. Signup/profile HTTP wiring, verification delivery/completion
+and the public Sendico HTTP adapter remain explicit work in the
+[architecture plan](../docs/architecture/bff.md). The sole Sendico organization
+reference belongs to that adapter's configuration, never to local customers.

backend/README.md

@@ -1,14 +1,41 @@
-# SXCHNGE backend
+# SXCHNGE BFF
 
-Reserved for a small backend for frontend (BFF) using a supported Sendico API. No service, runtime, or dependencies have been initialized yet.
+A locally owned copy of Sendico's reusable BFF runtime, authentication/session
+stack and customer account service. See [provenance](PROVENANCE.md) and the
+[architecture and public API plan](../docs/architecture/bff.md).
 
-Planned responsibilities:
+SXCHNGE owns its customers and authentication. SXCHNGE itself is one organization
+in Sendico. Provider integration uses only Sendico's public HTTP API; the pinned
+[OpenAPI snapshot](contracts/sendico/api.yaml) is isolated from local models.
 
-- Consumer authentication and sessions, with a stable mapping to organization-scoped Sendico customer references.
-- Consumer-authorized access to onboarding, quotes, orders, and transaction history.
-- Product-specific orchestration and presentation of Sendico KYC, eligibility, and remaining-limit responses.
-- Server-side integration credentials and request correlation with Sendico.
+## Run locally
 
-Sendico owns payment execution, authoritative KYC evidence and verification records, policy evaluation, and limit reservations/enforcement. Do not copy its existing BFF or import local Sendico implementation modules.
+Requires Go 1.27 and an SXCHNGE-owned MongoDB replica set for transactions.
+Copy `config.example.yml` to an untracked `config.yml`. Set:
 
-Before implementation, agree on customer registration and identity mapping, customer KYC operations, eligibility/limits reads, customer-scoped payment access, and retry/idempotency behavior. Validate consumer isolation even when multiple customers use the same sxchnge organization and integration principal.
+- `SXCHNGE_MONGO_URI`: URI for the local SXCHNGE database.
+- `SXCHNGE_JWT_SECRET`: private random signing key, at least 32 bytes for HS256.
+- `SXCHNGE_DOMAIN`: local API hostname (for example `localhost:8082`).
+- `SXCHNGE_API_PROTOCOL`: `http` locally, `https` in deployment.
+- `SXCHNGE_API_ENDPOINT`: `/api/v1`.
+
+The runtime starts against an empty SXCHNGE database and creates its indexes.
+No organization, role, policy or seed is required.
+Run `make run-backend` from the repository root. The copied CLI accepts
+`-config.file`, `-version` and `-debug`. Configure exact browser origins in YAML;
+secure refresh cookies require HTTPS for browser session testing.
+
+The runtime mounts `/api/v1/health` and the copied account login, API login,
+refresh, rotation and logout handlers. Customer/client records must exist in the
+local database. The account service creates customers and activation tokens
+atomically, and deletes customers with session revocation. It is initialized locally; signup/profile and
+verification-delivery/completion routes are the next wiring work. This is a
+bootstrap, not a finished authentication deployment. No Sendico calls are made.
+
+## Validate
+
+Run `make test` and `make lint-backend`. Backend tests include real MongoDB
+integration tests through Testcontainers, so Docker must be running.
+`make test-backend` runs the backend suite with the race detector.
+Architecture checks reject private Sendico imports/transports and ad hoc error
+constructors. The frontend still uses dummy services; no Flutter source changed.

backend/cmd/bff/main.go

@@ -0,0 +1,21 @@
+// Adapted from Sendico api/edge/product/main.go; see PROVENANCE.md.
+package main
+
+import (
+	"git.sendico.io/tech/sxchnge/bff/edge/shared/appversion"
+	"git.sendico.io/tech/sxchnge/bff/edge/shared/server"
+	"git.sendico.io/tech/sxchnge/bff/internal/profile"
+	"git.sendico.io/tech/sxchnge/bff/pkg/mlogger"
+	application "git.sendico.io/tech/sxchnge/bff/pkg/server"
+	smain "git.sendico.io/tech/sxchnge/bff/pkg/server/main"
+	"os"
+)
+
+func factory(logger mlogger.Logger, file string, debug bool) (application.Application, error) {
+	return server.Create(logger, file, debug, profile.Runtime())
+}
+func main() {
+	if smain.RunServer("sxchnge.bff", appversion.Create(), factory) != nil {
+		os.Exit(1)
+	}
+}

backend/config.example.yml

@@ -0,0 +1,33 @@
+# SXCHNGE-owned Mongo database and JWT key. Never point these at Sendico.
+http_server:
+  listen_address: 127.0.0.1:8082
+  read_header_timeout: 5
+  shutdown_timeout: 10
+database:
+  driver: mongodb
+  settings:
+    uri_env: SXCHNGE_MONGO_URI
+    database: sxchnge
+api:
+  middleware:
+    domain_env: SXCHNGE_DOMAIN
+    api_endpoint_env: SXCHNGE_API_ENDPOINT
+    api_protocol_env: SXCHNGE_API_PROTOCOL
+    signature:
+      algorithm: HS256
+      secret_key_env: SXCHNGE_JWT_SECRET
+    CORS:
+      allowed_origins: ["http://localhost:5126"]
+      allowed_methods: ["GET", "POST", "PATCH", "DELETE", "OPTIONS"]
+      allowed_headers: ["Content-Type", "Authorization", "X-Auth-Transport", "X-CSRF-Protection"]
+      allow_credentials: true
+      max_age: 300
+    token:
+      expiration_hours:
+        account: 1
+        refresh: 720
+      length: 32
+    password:
+      token_length: 32
+      check:
+        min_length: 12

backend/contracts/sendico/api.yaml

@@ -0,0 +1,129 @@
+openapi: 3.1.0
+info:
+  title: Sendico API Contract
+  version: 4.2.37
+  summary: Minimal client contract for authenticated BFF flows.
+  description: |
+    OpenAPI 3.1 contract focused on authenticated client flows exposed by the BFF:
+    authentication, verification, recipients, payment methods, payments, wallets,
+    and ledger account history.
+servers:
+  - url: /api/v1
+    description: Main HTTP API base path
+
+tags:
+  - name: Auth
+    description: Authentication and token lifecycle
+  - name: Accounts
+    description: Account auth responses used by login/verification
+  - name: Verification
+    description: Pending-account code verification
+  - name: Organizations
+    description: Organization selection for payment operations
+  - name: Recipients
+    description: Recipient CRUD and archive flows
+  - name: Payment Methods
+    description: Payment method CRUD and archive flows
+  - name: Callbacks
+    description: Webhook callback subscription CRUD and signing material rotation for HMAC and detached-JWS callbacks
+  - name: Payments
+    description: Quotation and payment orchestration
+  - name: Wallets
+    description: Managed wallet metadata and balances
+  - name: Ledger Accounts
+    description: Ledger account balances and account-history operations
+
+paths:
+  /accounts/login:
+    $ref: ./api/accounts/auth_login.yaml
+  /accounts/login/api:
+    $ref: ./api/accounts/auth_login_api.yaml
+  /accounts/rotate:
+    $ref: ./api/accounts/auth_rotate.yaml
+  /accounts/refresh:
+    $ref: ./api/accounts/auth_refresh.yaml
+
+  /verification:
+    $ref: ./api/verification/create.yaml
+  /verification/resend:
+    $ref: ./api/verification/resend.yaml
+  /verification/verify:
+    $ref: ./api/verification/verify.yaml
+
+  /organizations:
+    $ref: ./api/organizations/root.yaml
+  /organizations/{org_ref}:
+    $ref: ./api/organizations/get.yaml
+
+  /recipients/list/{org_ref}/{organizations_ref}:
+    $ref: ./api/recipients/list.yaml
+  /recipients/{org_ref}:
+    $ref: ./api/recipients/create.yaml
+  /recipients/{recipients_ref}:
+    $ref: ./api/recipients/object.yaml
+  /recipients:
+    $ref: ./api/recipients/update.yaml
+  /recipients/archive/{org_ref}/{recipients_ref}:
+    $ref: ./api/recipients/archive.yaml
+
+  /payment_methods/accounts/{organizations_ref}/{accounts_ref}:
+    $ref: ./api/payment_methods/accounts.yaml
+  /payment_methods/recipients/{organizations_ref}/{recipients_ref}:
+    $ref: ./api/payment_methods/recipients.yaml
+  /payment_methods/{organizations_ref}/{payment_methods_ref}:
+    $ref: ./api/payment_methods/object.yaml
+  /payment_methods/archive/{organizations_ref}/{payment_methods_ref}:
+    $ref: ./api/payment_methods/archive.yaml
+
+  /callbacks/list/{org_ref}/{organizations_ref}:
+    $ref: ./api/callbacks/list.yaml
+  /callbacks/{org_ref}:
+    $ref: ./api/callbacks/create.yaml
+  /callbacks/{callbacks_ref}:
+    $ref: ./api/callbacks/object.yaml
+  /callbacks:
+    $ref: ./api/callbacks/update.yaml
+  /callbacks/archive/{org_ref}/{callbacks_ref}:
+    $ref: ./api/callbacks/archive.yaml
+  /callbacks/rotate-secret/{callbacks_ref}:
+    $ref: ./api/callbacks/rotate_secret.yaml
+
+  /payments/quote/{organizations_ref}:
+    $ref: ./api/payments/quote.yaml
+  /payments/multiquote/{organizations_ref}:
+    $ref: ./api/payments/multiquote.yaml
+  /payments/immediate/{organizations_ref}:
+    $ref: ./api/payments/immediate.yaml
+  /payments/by-quote/{organizations_ref}:
+    $ref: ./api/payments/by_quote.yaml
+  /payments/by-multiquote/{organizations_ref}:
+    $ref: ./api/payments/by_multiquote.yaml
+  /payments/by-ref/{payments_ref}:
+    $ref: ./api/payments/object.yaml
+  /payments/{organizations_ref}:
+    $ref: ./api/payments/list.yaml
+  /payments/documents/certificate/{organizations_ref}:
+    $ref: ./api/payments/documents_certificate.yaml
+  /payments/registry/{organizations_ref}:
+    $ref: ./api/payments/registry.yaml
+  /payments/registry/refresh/{organizations_ref}:
+    $ref: ./api/payments/registry_refresh.yaml
+  /payments/fx/currencies/{organizations_ref}:
+    $ref: ./api/payments/fx_currencies.yaml
+  /payments/fx/directions/{organizations_ref}:
+    $ref: ./api/payments/fx_directions.yaml
+  /chain_wallets/{organizations_ref}/assets:
+    $ref: ./api/wallets/assets.yaml
+  /ledger_accounts/{organizations_ref}/{ledger_account_ref}/balance:
+    $ref: ./api/ledger_accounts/balance.yaml
+  /ledger_accounts/{organizations_ref}/{ledger_account_ref}/operations:
+    $ref: ./api/ledger_accounts/operations.yaml
+  /ledger_accounts/{organizations_ref}/{ledger_account_ref}/operations/{entry_ref}:
+    $ref: ./api/ledger_accounts/operation.yaml
+
+components:
+  securitySchemes:
+    bearerAuth:
+      type: http
+      scheme: bearer
+      bearerFormat: JWT

backend/contracts/sendico/api/accounts/auth_login.yaml

@@ -0,0 +1,29 @@
+post:
+  tags: [Accounts, Auth]
+  summary: Login using email/password and receive pending verification token
+  description: |
+    Validates account credentials and returns a short-lived `pendingToken`.
+    This endpoint does not return final access/refresh tokens; complete verification flow via `/verification/verify`.
+  operationId: accountsLogin
+  requestBody:
+    $ref: ./bodies/auth.yaml#/components/requestBodies/LoginBody
+  responses:
+    '202':
+      description: Pending verification token issued
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/auth.yaml#/components/schemas/PendingLoginData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/accounts/auth_login_api.yaml

@@ -0,0 +1,30 @@
+post:
+  tags: [Accounts, Auth]
+  summary: API login using email/password and client credentials
+  description: |
+    Validates account credentials and eligible API client credentials, then returns final auth payload.
+    This endpoint bypasses login OTP/2FA and is intended only for approved API clients.
+    If the client definition includes `allowedCIDRs`, request source IP must match one of those CIDRs.
+  operationId: accountsApiLogin
+  requestBody:
+    $ref: ./bodies/auth.yaml#/components/requestBodies/ApiLoginBody
+  responses:
+    '200':
+      description: Login successful
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/auth.yaml#/components/schemas/LoginData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/accounts/auth_refresh.yaml

@@ -0,0 +1,31 @@
+post:
+  tags: [Accounts, Auth]
+  summary: Refresh access token by refresh token
+  description: |
+    Validates refresh token + session identifiers and issues a new access token.
+    Use this endpoint when refresh token stays the same.
+  operationId: accountsRefreshAccessToken
+  requestBody:
+    $ref: ./bodies/auth.yaml#/components/requestBodies/RefreshTokenBody
+  responses:
+    '200':
+      description: Access token refreshed
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/auth.yaml#/components/schemas/AccountAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/accounts/auth_rotate.yaml

@@ -0,0 +1,31 @@
+post:
+  tags: [Accounts, Auth]
+  summary: Rotate refresh token and issue new access/refresh tokens
+  description: |
+    Validates refresh token + session identifiers and returns a new token pair.
+    Use this endpoint when replacing both access and refresh tokens.
+  operationId: accountsRotateRefreshToken
+  requestBody:
+    $ref: ./bodies/auth.yaml#/components/requestBodies/RefreshTokenBody
+  responses:
+    '200':
+      description: New token pair issued
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/auth.yaml#/components/schemas/LoginData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/accounts/bodies/auth.yaml

@@ -0,0 +1,24 @@
+components:
+  requestBodies:
+    LoginBody:
+      description: JSON credentials payload for standard login.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/auth.yaml#/components/schemas/LoginRequest
+    ApiLoginBody:
+      description: JSON credentials payload for API client login.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/auth.yaml#/components/schemas/ApiLoginRequest
+
+    RefreshTokenBody:
+      description: JSON payload containing session and refresh token data.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/auth.yaml#/components/schemas/RefreshTokenRequest

backend/contracts/sendico/api/accounts/request/auth.yaml

@@ -0,0 +1,34 @@
+components:
+  schemas:
+    LoginRequest:
+      type: object
+      additionalProperties: false
+      required:
+        - login
+      properties:
+        clientId:
+          type: string
+          description: Client identifier bound to refresh token lifecycle and client policy checks.
+        deviceId:
+          type: string
+          description: Device/server identifier associated with the client session.
+        login:
+          $ref: ../../../models/auth/login_data.yaml#/components/schemas/LoginData
+
+    ApiLoginRequest:
+      allOf:
+        - $ref: ./auth.yaml#/components/schemas/LoginRequest
+        - type: object
+          additionalProperties: false
+          required:
+            - clientId
+            - deviceId
+            - clientSecret
+          properties:
+            clientSecret:
+              type: string
+              format: password
+              description: Client secret for `client_secret_post` authentication.
+
+    RefreshTokenRequest:
+      $ref: ../../../models/auth/client_refresh_token.yaml#/components/schemas/ClientRefreshToken

backend/contracts/sendico/api/accounts/response/auth.yaml

@@ -0,0 +1,62 @@
+components:
+  schemas:
+    AccountAuthData:
+      description: Authentication response containing account profile and access token.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - account
+      properties:
+        accessToken:
+          description: Access token used for authenticated requests.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        account:
+          description: Authenticated account data.
+          $ref: ../../../models/account/account.yaml#/components/schemas/AccountData
+
+    LoginData:
+      description: Full login response including access and refresh tokens.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - account
+        - refreshToken
+      properties:
+        accessToken:
+          description: Access token used for authenticated requests.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        account:
+          description: Authenticated account data.
+          $ref: ../../../models/account/account.yaml#/components/schemas/AccountData
+        refreshToken:
+          description: Refresh token used to obtain a new access token.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+
+    PendingLoginData:
+      description: Pending login response requiring additional verification.
+      type: object
+      additionalProperties: false
+      required:
+        - account
+        - pendingToken
+        - target
+      properties:
+        account:
+          description: Interim authentication payload prepared for verification completion.
+          type: object
+          additionalProperties: false
+          properties:
+            accessToken:
+              description: Temporary access token issued before verification is completed.
+              $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+            account:
+              description: Account data associated with the pending login flow.
+              $ref: ../../../models/account/account.yaml#/components/schemas/AccountData
+        pendingToken:
+          description: Token proving the pending verification session.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        target:
+          description: Verification target destination (for example email or phone).
+          type: string

backend/contracts/sendico/api/callbacks/archive.yaml

@@ -0,0 +1,37 @@
+get:
+  tags: [Callbacks]
+  summary: Archive/unarchive callback subscription
+  description: Sets callback archive state by `callbacks_ref` and required `archived` query parameter.
+  operationId: callbacksArchive
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/org_ref.yaml#/components/parameters/OrgRef
+    - $ref: ../parameters/callbacks_ref.yaml#/components/parameters/CallbacksRef
+    - name: archived
+      in: query
+      required: true
+      description: Target archive value to set on the callback.
+      schema:
+        type: boolean
+    - $ref: ../parameters/cascade.yaml#/components/parameters/Cascade
+  responses:
+    '200':
+      description: Archive state updated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/callback.yaml#/components/schemas/CallbacksAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/callbacks/bodies/callback.yaml

@@ -0,0 +1,17 @@
+components:
+  requestBodies:
+    CallbackCreateBody:
+      description: JSON body containing callback endpoint configuration for create.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/callback.yaml#/components/schemas/CallbackCreateRequest
+
+    CallbackUpdateBody:
+      description: JSON body containing callback endpoint configuration for update.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/callback.yaml#/components/schemas/CallbackUpdateRequest

backend/contracts/sendico/api/callbacks/create.yaml

@@ -0,0 +1,33 @@
+post:
+  tags: [Callbacks]
+  summary: Create callback subscription
+  description: Creates callback subscription for the organization identified by `org_ref`.
+  operationId: callbacksCreate
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/org_ref.yaml#/components/parameters/OrgRef
+  requestBody:
+    $ref: ./bodies/callback.yaml#/components/requestBodies/CallbackCreateBody
+  responses:
+    '201':
+      description: Callback created
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/callback.yaml#/components/schemas/CallbacksAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/callbacks/list.yaml

@@ -0,0 +1,35 @@
+get:
+  tags: [Callbacks]
+  summary: List callback subscriptions
+  description: |
+    Lists callbacks for the given organization context.
+    The route currently includes both `org_ref` and `organizations_ref`; the handler resolves organization context from `org_ref` and ignores `organizations_ref`.
+  operationId: callbacksList
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/org_ref.yaml#/components/parameters/OrgRef
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/limit.yaml#/components/parameters/Limit
+    - $ref: ../parameters/offset.yaml#/components/parameters/Offset
+    - $ref: ../parameters/archived.yaml#/components/parameters/Archived
+  responses:
+    '200':
+      description: Callback list
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/callback.yaml#/components/schemas/CallbacksAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/callbacks/object.yaml

@@ -0,0 +1,64 @@
+get:
+  tags: [Callbacks]
+  summary: Get callback subscription
+  description: Returns callback subscription by `callbacks_ref`.
+  operationId: callbacksGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/callbacks_ref.yaml#/components/parameters/CallbacksRef
+  responses:
+    '200':
+      description: Callback data
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/callback.yaml#/components/schemas/CallbacksAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError
+
+delete:
+  tags: [Callbacks]
+  summary: Delete callback subscription
+  description: Deletes callback by reference.
+  operationId: callbacksDelete
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/callbacks_ref.yaml#/components/parameters/CallbacksRef
+    - $ref: ../parameters/cascade.yaml#/components/parameters/Cascade
+  responses:
+    '200':
+      description: Callback deleted
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/callback.yaml#/components/schemas/CallbacksAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/callbacks/request/callback.yaml

@@ -0,0 +1,113 @@
+components:
+  schemas:
+    CallbackBackoffInput:
+      description: Optional retry backoff overrides. Non-positive values currently fall back to server defaults.
+      type: object
+      additionalProperties: false
+      properties:
+        minDelayMs:
+          type: integer
+        maxDelayMs:
+          type: integer
+
+    CallbackRetryPolicyInput:
+      description: Optional retry and signing overrides. Omitted or non-positive numeric values currently fall back to server defaults.
+      type: object
+      additionalProperties: false
+      properties:
+        backoff:
+          $ref: '#/components/schemas/CallbackBackoffInput'
+        signingMode:
+          description: |
+            Optional signing mode. Canonical values are documented here; current handler also accepts legacy aliases such as `hmac`, `hmac-sha256`, `jws-eddsa-ed25519`, `jws+eddsa-ed25519`, `jws_eddsa`, and `eddsa_ed25519`.
+          type: string
+          enum:
+            - none
+            - hmac_sha256
+            - jws_eddsa_ed25519
+        headers:
+          type: object
+          additionalProperties:
+            type: string
+        maxAttempts:
+          type: integer
+        requestTimeoutMs:
+          type: integer
+
+    CallbackCreateRequest:
+      description: |
+        Request payload used to create a callback configuration.
+        Only `url` is hard-required by current create logic. Other mutable fields are optional and defaulted by the handler when omitted.
+      type: object
+      additionalProperties: false
+      required:
+        - url
+      properties:
+        name:
+          description: Optional callback display name. When omitted, the handler defaults it to `url`.
+          type: string
+        description:
+          description: Optional callback description.
+          type: string
+          nullable: true
+        status:
+          description: |
+            Optional callback status. Canonical values are documented here; current handler also accepts `enabled` and `inactive` aliases.
+          type: string
+          enum:
+            - active
+            - disabled
+        url:
+          description: Absolute HTTPS callback endpoint URL.
+          type: string
+          format: uri
+        eventTypes:
+          description: Optional callback event types. When omitted or empty, the handler defaults this list.
+          type: array
+          items:
+            type: string
+        retryPolicy:
+          $ref: '#/components/schemas/CallbackRetryPolicyInput'
+
+    CallbackUpdateRequest:
+      description: |
+        Request payload used to update a callback configuration.
+        The current PUT handler requires `id`, `organizationRef`, and `url`. Other mutable fields are optional, but omitted values may be reset to handler defaults during normalization.
+      type: object
+      additionalProperties: false
+      required:
+        - id
+        - organizationRef
+        - url
+      properties:
+        id:
+          description: Callback identifier to update.
+          $ref: ../../../models/objectid.yaml#/components/schemas/ObjectId
+        organizationRef:
+          description: Organization identifier carried in the stored callback record and currently required by the update path.
+          $ref: ../../../models/objectid.yaml#/components/schemas/ObjectId
+        name:
+          description: Optional callback display name. When omitted, the handler defaults it to `url`.
+          type: string
+        description:
+          description: Optional callback description.
+          type: string
+          nullable: true
+        status:
+          description: |
+            Optional callback status. Canonical values are documented here; current handler also accepts `enabled` and `inactive` aliases.
+          type: string
+          enum:
+            - active
+            - disabled
+        url:
+          description: Absolute HTTPS callback endpoint URL.
+          type: string
+          format: uri
+        eventTypes:
+          description: Optional callback event types. When omitted or empty, the handler defaults this list.
+          type: array
+          items:
+            type: string
+        retryPolicy:
+          $ref: '#/components/schemas/CallbackRetryPolicyInput'

backend/contracts/sendico/api/callbacks/response/callback.yaml

@@ -0,0 +1,22 @@
+components:
+  schemas:
+    CallbacksAuthData:
+      description: Authenticated response payload containing callback configurations.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - callbacks
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        callbacks:
+          description: Collection of callbacks configured for the authenticated scope. JWS-signed callbacks expose read-only verification JWKs via `callbacks[].signingKeys`.
+          type: array
+          items:
+            $ref: ../../../models/callback/callback.yaml#/components/schemas/Callback
+        generatedSigningSecret:
+          description: Newly generated signing secret when HMAC signing material is created or rotated. JWS-signed callbacks do not populate this field.
+          type: string
+          nullable: true

backend/contracts/sendico/api/callbacks/rotate_secret.yaml

@@ -0,0 +1,31 @@
+post:
+  tags: [Callbacks]
+  summary: Rotate callback signing material
+  description: Rotates the active signing material for the callback. HMAC callbacks generate and return a new shared secret once. `jws_eddsa_ed25519` callbacks generate a new Ed25519 keypair, expose the new active verification JWK on normal callback reads, and keep retiring verification keys visible for 24 hours.
+  operationId: callbacksRotateSecret
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/callbacks_ref.yaml#/components/parameters/CallbacksRef
+  responses:
+    '200':
+      description: Callback signing material rotated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/callback.yaml#/components/schemas/CallbacksAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/callbacks/update.yaml

@@ -0,0 +1,31 @@
+put:
+  tags: [Callbacks]
+  summary: Update callback subscription
+  description: Updates callback subscription fields. The current handler requires `id`, `organizationRef`, and `url`; omitted mutable fields may be reset to defaults.
+  operationId: callbacksUpdate
+  security:
+    - bearerAuth: []
+  requestBody:
+    $ref: ./bodies/callback.yaml#/components/requestBodies/CallbackUpdateBody
+  responses:
+    '200':
+      description: Callback updated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/callback.yaml#/components/schemas/CallbacksAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/ledger_accounts/balance.yaml

@@ -0,0 +1,58 @@
+get:
+  tags: [Ledger Accounts]
+  summary: Get ledger account balance
+  description: |
+    Returns the canonical balance for the requested ledger account.
+
+    Without `as_of`, the response is the current materialized balance and includes
+    current metadata fields `version` and `lastUpdated`.
+
+    With `as_of`, the response is an event-time accounting balance reconstructed
+    from posted statement-entry deltas where `eventTime <= as_of`. Entries exactly
+    equal to `as_of` are included. This is not a historical snapshot of materialized
+    balance state and not "what the system knew" at that clock time. Late or
+    backdated postings with older `eventTime` can change historical responses for
+    the same `as_of`. Historical responses include `ledgerAccountRef`, `balance`,
+    and canonical UTC `asOf`, and omit `version` and `lastUpdated` because no
+    historical snapshot/version semantics are defined.
+
+    Historical balance is valid only if every account-affecting committed posting
+    writes matching statement entries in the same transaction as balance updates.
+  operationId: ledgerAccountBalanceGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/ledger_account_ref.yaml#/components/parameters/LedgerAccountRef
+    - name: as_of
+      in: query
+      required: false
+      description: |
+        Optional RFC3339 event-time cutoff for historical balance reconstruction.
+        Timezone offsets are accepted and returned as canonical UTC `asOf`.
+      schema:
+        type: string
+        format: date-time
+      example: '2026-04-23T14:30:00+02:00'
+  responses:
+    '200':
+      description: Ledger account balance
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/balance.yaml#/components/schemas/LedgerAccountBalanceData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/ledger_accounts/operation.yaml

@@ -0,0 +1,36 @@
+get:
+  tags: [Ledger Accounts]
+  summary: Get ledger account operation detail
+  description: |
+    Returns the account-history projection for `entry_ref` within the requested ledger account.
+    This is not a general journal-entry read API.
+    The endpoint returns `404` when the entry is not part of the requested account's visible history.
+  operationId: ledgerAccountOperationsGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/ledger_account_ref.yaml#/components/parameters/LedgerAccountRef
+    - $ref: ../parameters/entry_ref.yaml#/components/parameters/EntryRef
+  responses:
+    '200':
+      description: Ledger account operation detail
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/operation.yaml#/components/schemas/LedgerAccountOperationData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/ledger_accounts/operations.yaml

@@ -0,0 +1,36 @@
+get:
+  tags: [Ledger Accounts]
+  summary: List ledger account operations
+  description: |
+    Returns account-history summary projections for the requested ledger account.
+    Public HTTP pagination supports only `limit` and `offset`.
+    Results are ordered by `version` descending and `entry_ref` descending.
+    Unsupported query parameters, including `archived`, are rejected.
+  operationId: ledgerAccountOperationsList
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/ledger_account_ref.yaml#/components/parameters/LedgerAccountRef
+    - $ref: ../parameters/limit.yaml#/components/parameters/Limit
+    - $ref: ../parameters/offset.yaml#/components/parameters/Offset
+  responses:
+    '200':
+      description: Ledger account operation summaries
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/operation.yaml#/components/schemas/LedgerAccountOperationsData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/ledger_accounts/response/balance.yaml

@@ -0,0 +1,15 @@
+components:
+  schemas:
+    LedgerAccountBalanceData:
+      description: Response payload containing a ledger account balance.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - balance
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        balance:
+          $ref: ../../../models/ledger/balance.yaml#/components/schemas/LedgerAccountBalance

backend/contracts/sendico/api/ledger_accounts/response/operation.yaml

@@ -0,0 +1,33 @@
+components:
+  schemas:
+    LedgerAccountOperationsData:
+      description: Response payload containing ledger account history summaries.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - operations
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        operations:
+          description: Account-history summaries ordered by `version DESC, entryRef DESC`.
+          type: array
+          items:
+            $ref: ../../../models/ledger/operation.yaml#/components/schemas/LedgerAccountOperationSummary
+
+    LedgerAccountOperationData:
+      description: Response payload containing a single ledger account history projection.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - operation
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        operation:
+          description: Account-history projection for the requested entry and ledger account.
+          $ref: ../../../models/ledger/operation.yaml#/components/schemas/LedgerAccountOperation

backend/contracts/sendico/api/organizations/get.yaml

@@ -0,0 +1,29 @@
+get:
+  tags: [Organizations]
+  summary: Get organization by reference
+  description: Fetches a single organization available to the authenticated account.
+  operationId: organizationsGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/org_ref.yaml#/components/parameters/OrgRef
+  responses:
+    '200':
+      description: Organization details
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/organization.yaml#/components/schemas/OrganizationsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/organizations/response/organization.yaml

@@ -0,0 +1,18 @@
+components:
+  schemas:
+    OrganizationsAuthData:
+      description: Authenticated response payload containing organizations.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - organizations
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        organizations:
+          description: Collection of organizations available to the authenticated account.
+          type: array
+          items:
+            $ref: ../../../models/organization/organization.yaml#/components/schemas/Organization

backend/contracts/sendico/api/organizations/root.yaml

@@ -0,0 +1,27 @@
+get:
+  tags: [Organizations]
+  summary: List organizations of current account
+  description: Returns organizations the authenticated account can access.
+  operationId: organizationsList
+  security:
+    - bearerAuth: []
+  responses:
+    '200':
+      description: Organizations list
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/organization.yaml#/components/schemas/OrganizationsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/parameters/accounts_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    AccountsRef:
+      name: accounts_ref
+      in: path
+      required: true
+      description: Account reference, 24 hex chars.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/archived.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    Archived:
+      name: archived
+      in: query
+      required: false
+      description: Filter by archive flag. `true` returns archived records, `false` returns active records.
+      schema:
+        type: boolean

backend/contracts/sendico/api/parameters/callbacks_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    CallbacksRef:
+      name: callbacks_ref
+      in: path
+      required: true
+      description: Callback subscription reference, 24 hex chars.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/cascade.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    Cascade:
+      name: cascade
+      in: query
+      required: false
+      description: If `true`, apply operation to dependent objects where cascade is supported.
+      schema:
+        type: boolean

backend/contracts/sendico/api/parameters/cursor.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    Cursor:
+      name: cursor
+      in: query
+      required: false
+      description: Opaque cursor from a previous page response (`page.next_cursor`).
+      schema:
+        type: string

backend/contracts/sendico/api/parameters/entry_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    EntryRef:
+      name: entry_ref
+      in: path
+      required: true
+      description: Statement entry reference within the requested ledger account history.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/filter_states.yaml

@@ -0,0 +1,11 @@
+components:
+  parameters:
+    FilterStates:
+      name: filter_states
+      in: query
+      required: false
+      description: |
+        Additional payment state filter. Accepts one value or comma-separated values.
+        Same semantics as `state`/`states`.
+      schema:
+        type: string

backend/contracts/sendico/api/parameters/ledger_account_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    LedgerAccountRef:
+      name: ledger_account_ref
+      in: path
+      required: true
+      description: Ledger account reference that scopes the account-history read.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/limit.yaml

@@ -0,0 +1,11 @@
+components:
+  parameters:
+    Limit:
+      name: limit
+      in: query
+      description: Max number of items to return. Parsed as non-negative int64.
+      required: false
+      schema:
+        type: integer
+        format: int64
+        minimum: 0

backend/contracts/sendico/api/parameters/offset.yaml

@@ -0,0 +1,11 @@
+components:
+  parameters:
+    Offset:
+      name: offset
+      in: query
+      description: Number of items to skip. Parsed as non-negative int64.
+      required: false
+      schema:
+        type: integer
+        format: int64
+        minimum: 0

backend/contracts/sendico/api/parameters/org_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    OrgRef:
+      name: org_ref
+      in: path
+      required: true
+      description: Organization reference in BFF route format, 24 hex chars.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/organizations_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    OrganizationsRef:
+      name: organizations_ref
+      in: path
+      required: true
+      description: Organization reference used by payments/payment-methods/recipients routes.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/payment_methods_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    Payment MethodsRef:
+      name: payment_methods_ref
+      in: path
+      required: true
+      description: Payment method reference, 24 hex chars.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/payments_ref.yaml

@@ -0,0 +1,10 @@
+components:
+  parameters:
+    PaymentsRef:
+      name: payments_ref
+      in: path
+      required: true
+      description: Stable payment reference.
+      schema:
+        type: string
+        minLength: 1

backend/contracts/sendico/api/parameters/recipients_ref.yaml

@@ -0,0 +1,9 @@
+components:
+  parameters:
+    RecipientsRef:
+      name: recipients_ref
+      in: path
+      required: true
+      description: Recipient reference, 24 hex chars.
+      schema:
+        $ref: ../../models/objectid.yaml#/components/schemas/ObjectId

backend/contracts/sendico/api/parameters/state.yaml

@@ -0,0 +1,11 @@
+components:
+  parameters:
+    State:
+      name: state
+      in: query
+      required: false
+      description: |
+        Payment state filter. Accepts aliases like `accepted`, `settled`, `failed`
+        or canonical values like `orchestration_state_created`.
+      schema:
+        type: string

backend/contracts/sendico/api/parameters/states.yaml

@@ -0,0 +1,10 @@
+components:
+  parameters:
+    States:
+      name: states
+      in: query
+      required: false
+      description: |
+        Multi-state filter. Provide a comma-separated list with same accepted values as `state`.
+      schema:
+        type: string

backend/contracts/sendico/api/payment_methods/accounts.yaml

@@ -0,0 +1,74 @@
+get:
+  tags: [Payment Methods]
+  summary: List account-owned payment methods
+  description: |
+    Returns payment methods owned by `accounts_ref` within `organizations_ref`.
+    Supports offset pagination and optional archive filtering.
+  operationId: paymentMethodsListAccountOwned
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/accounts_ref.yaml#/components/parameters/AccountsRef
+    - $ref: ../parameters/limit.yaml#/components/parameters/Limit
+    - $ref: ../parameters/offset.yaml#/components/parameters/Offset
+    - $ref: ../parameters/archived.yaml#/components/parameters/Archived
+  responses:
+    '200':
+      description: Payment methods list
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError
+
+post:
+  tags: [Payment Methods]
+  summary: Create account-owned payment method
+  description: Creates a payment method owned by `accounts_ref` inside `organizations_ref`.
+  operationId: paymentMethodsCreateAccountOwned
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/accounts_ref.yaml#/components/parameters/AccountsRef
+  requestBody:
+    $ref: ./bodies/payment_method.yaml#/components/requestBodies/PaymentMethodCreateBody
+  responses:
+    '201':
+      description: Payment method created
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payment_methods/archive.yaml

@@ -0,0 +1,36 @@
+post:
+  tags: [Payment Methods]
+  summary: Archive/unarchive payment method
+  description: Sets payment method archive state by `payment_methods_ref` and required `archived` query parameter.
+  operationId: paymentMethodsArchive
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/payment_methods_ref.yaml#/components/parameters/Payment MethodsRef
+    - name: archived
+      in: query
+      required: true
+      description: Target archive value to set on the payment method.
+      schema:
+        type: boolean
+  responses:
+    '200':
+      description: Archive state updated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payment_methods/bodies/payment_method.yaml

@@ -0,0 +1,17 @@
+components:
+  requestBodies:
+    PaymentMethodCreateBody:
+      description: JSON body containing a payment method definition for create.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/payment_method.yaml#/components/schemas/PaymentMethodCreateRequest
+
+    PaymentMethodUpdateBody:
+      description: JSON body containing a payment method definition for update.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/payment_method.yaml#/components/schemas/PaymentMethodUpdateRequest

backend/contracts/sendico/api/payment_methods/object.yaml

@@ -0,0 +1,102 @@
+get:
+  tags: [Payment Methods]
+  summary: Get payment method
+  description: Returns payment method by `payment_methods_ref` inside `organizations_ref`.
+  operationId: paymentMethodsGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/payment_methods_ref.yaml#/components/parameters/Payment MethodsRef
+  responses:
+    '200':
+      description: Payment method data
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError
+
+patch:
+  tags: [Payment Methods]
+  summary: Update payment method
+  description: Updates mutable payment method fields for the record identified by `payment_methods_ref` inside `organizations_ref`.
+  operationId: paymentMethodsUpdate
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/payment_methods_ref.yaml#/components/parameters/Payment MethodsRef
+  requestBody:
+    $ref: ./bodies/payment_method.yaml#/components/requestBodies/PaymentMethodUpdateBody
+  responses:
+    '200':
+      description: Payment method updated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError
+
+delete:
+  tags: [Payment Methods]
+  summary: Delete payment method
+  description: Deletes payment method by reference.
+  operationId: paymentMethodsDelete
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/payment_methods_ref.yaml#/components/parameters/Payment MethodsRef
+  responses:
+    '200':
+      description: Payment method deleted
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payment_methods/recipients.yaml

@@ -0,0 +1,74 @@
+get:
+  tags: [Payment Methods]
+  summary: List recipient-owned payment methods
+  description: |
+    Returns payment methods owned by `recipients_ref` within `organizations_ref`.
+    Supports offset pagination and optional archive filtering.
+  operationId: paymentMethodsListRecipientOwned
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/recipients_ref.yaml#/components/parameters/RecipientsRef
+    - $ref: ../parameters/limit.yaml#/components/parameters/Limit
+    - $ref: ../parameters/offset.yaml#/components/parameters/Offset
+    - $ref: ../parameters/archived.yaml#/components/parameters/Archived
+  responses:
+    '200':
+      description: Payment methods list
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError
+
+post:
+  tags: [Payment Methods]
+  summary: Create recipient-owned payment method
+  description: Creates a payment method owned by `recipients_ref` inside `organizations_ref`.
+  operationId: paymentMethodsCreateRecipientOwned
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/recipients_ref.yaml#/components/parameters/RecipientsRef
+  requestBody:
+    $ref: ./bodies/payment_method.yaml#/components/requestBodies/PaymentMethodCreateBody
+  responses:
+    '201':
+      description: Payment method created
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment_method.yaml#/components/schemas/Payment MethodsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payment_methods/request/payment_method.yaml

@@ -0,0 +1,42 @@
+components:
+  schemas:
+    PaymentMethodBaseRequest:
+      type: object
+      additionalProperties: false
+      properties:
+        name:
+          description: Optional human-readable payment method name.
+          type: string
+        description:
+          description: Optional free-form payment method description.
+          type: string
+          nullable: true
+        type:
+          description: Payment method type discriminator.
+          $ref: ../../../external/payment_method_type.yaml#/components/schemas/PaymentMethodType
+        data:
+          description: |
+            Optional payment-method-type-specific payload.
+            For `type: bankAccount`, this uses the Russian bank-account
+            destination shape documented as `BankAccountEndpoint`.
+          type: object
+          additionalProperties: true
+        isMain:
+          description: Optional primary-method flag. When omitted, current handler behavior falls back to `false`.
+          type: boolean
+
+    PaymentMethodCreateRequest:
+      description: |
+        Request payload used to create a payment method.
+        Ownership comes from the route path. The body only carries mutable payment-method fields.
+      required:
+        - type
+      allOf:
+        - $ref: '#/components/schemas/PaymentMethodBaseRequest'
+
+    PaymentMethodUpdateRequest:
+      description: |
+        Request payload used to update a payment method.
+        This is a PATCH contract. Only `name`, `description`, `data`, and `isMain` are mutable.
+      allOf:
+        - $ref: '#/components/schemas/PaymentMethodBaseRequest'

backend/contracts/sendico/api/payment_methods/response/payment_method.yaml

@@ -0,0 +1,18 @@
+components:
+  schemas:
+    Payment MethodsAuthData:
+      description: Authenticated response payload containing payment methods.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - payment_methods
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        payment_methods:
+          description: Collection of payment methods available to the authenticated account.
+          type: array
+          items:
+            $ref: ../../../models/payment_method/payment_method.yaml#/components/schemas/PaymentMethod

backend/contracts/sendico/api/payments/bodies/payment.yaml

@@ -0,0 +1,33 @@
+components:
+  requestBodies:
+    QuotePaymentBody:
+      description: JSON payload used to request a quote for one payment intent.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/payment.yaml#/components/schemas/QuotePaymentRequest
+
+    QuotePaymentsBody:
+      description: JSON payload used to request quotes for multiple payment intents.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/payment.yaml#/components/schemas/QuotePaymentsRequest
+
+    InitiatePaymentBody:
+      description: JSON payload used to initiate a single payment.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/payment.yaml#/components/schemas/InitiatePaymentRequest
+
+    InitiatePaymentsBody:
+      description: JSON payload used to initiate multiple payments from a quote reference.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/payment.yaml#/components/schemas/InitiatePaymentsRequest

backend/contracts/sendico/api/payments/by_multiquote.yaml

@@ -0,0 +1,37 @@
+post:
+  tags: [Payments]
+  summary: Initiate payment batch by quote reference
+  description: |
+    Executes batch payment from a previously created multi-quote reference. If any quoted item
+    uses a raw `card` destination, that item's original quote must already include `exp_month`
+    and `exp_year`. Card-recipient AML screening occurs during execution, not quotation. An
+    unchanged payment item reuses its persisted compliance decision on idempotent execution
+    replay, avoiding a duplicate AML call. A definitive denial terminates that payment with
+    public `failureCode: failure_restriction` and `failureReason: aml_denied`.
+  operationId: paymentsInitiateBatchByQuote
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  requestBody:
+    $ref: ./bodies/payment.yaml#/components/requestBodies/InitiatePaymentsBody
+  responses:
+    '200':
+      description: Payment batch initiated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/PaymentsData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/by_quote.yaml

@@ -0,0 +1,41 @@
+post:
+  tags: [Payments]
+  summary: Initiate payment using quote reference
+  description: |
+    Executes one payment from an existing quote reference. If the quoted destination is raw
+    `card`, the original quote must already include `exp_month` and `exp_year`. Card-recipient
+    AML screening occurs during execution, not quotation. An unchanged payment reuses its
+    persisted compliance decision on idempotent execution replay, avoiding a duplicate AML call.
+    A definitive denial terminates the payment with public `failureCode: failure_restriction`
+    and `failureReason: aml_denied`.
+  operationId: paymentsInitiateByQuote
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  requestBody:
+    required: true
+    content:
+      application/json:
+        schema:
+          $ref: ./request/payment.yaml#/components/schemas/InitiatePaymentByQuoteRequest
+  responses:
+    '200':
+      description: Payment initiated by quote
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/PaymentData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/documents_certificate.yaml

@@ -0,0 +1,47 @@
+get:
+  tags: [Payments]
+  summary: Download payment certificate
+  description: |
+    Returns a generated payment certificate as binary content.
+    The payment must be settled; the BFF resolves certificate details from the payment reference.
+  operationId: paymentsGetPaymentCertificate
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - name: payment_ref
+      in: query
+      required: true
+      description: Settled payment reference used to generate the payment certificate.
+      schema:
+        type: string
+  responses:
+    '200':
+      description: Payment certificate file
+      content:
+        application/pdf:
+          schema:
+            type: string
+            format: binary
+        application/octet-stream:
+          schema:
+            type: string
+            format: binary
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError
+    '503':
+      description: Upstream service unavailable
+      content:
+        application/json:
+          schema:
+            $ref: ../response/response.yaml#/components/schemas/ErrorResponse

backend/contracts/sendico/api/payments/fx_currencies.yaml

@@ -0,0 +1,40 @@
+get:
+  tags: [Payments]
+  summary: List available FX currencies
+  description: |
+    Returns the BFF startup-cached Treasury Currency Catalog projection for
+    client-visible FX currencies. `decimals`, `scale`, and `displayScale` are
+    presentation fields backed by Treasury `display_scale`.
+    `accountingScaleCandidate` is informational only and must not be used by
+    clients to determine executable payout precision, quote precision, or
+    guaranteed provider support.
+    The endpoint is authenticated and authorized by `organizations_ref`, but the
+    returned catalogue is global rather than organization-customized. If Treasury
+    was unavailable at BFF startup while this endpoint was enabled, BFF fails
+    startup; if Treasury becomes unavailable after startup, BFF continues serving
+    the cached catalog revision.
+  operationId: paymentsFXCurrencies
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  responses:
+    '200':
+      description: FX currency catalogue projected from Treasury
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/FXCurrenciesData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '503':
+      $ref: ../response/operation.yaml#/components/responses/ServiceUnavailable

backend/contracts/sendico/api/payments/fx_directions.yaml

@@ -0,0 +1,48 @@
+get:
+  tags: [Payments]
+  summary: List available FX directions
+  description: |
+    Returns organization-level FX direction availability.
+
+    A returned direction means the organization has at least one eligible
+    direction-level route. It does not mean that every quote or payment for this
+    direction will be accepted. The actual route, gateway, limits, pricing, fees,
+    asset domain, and settlement details are resolved during quotation/payment
+    execution.
+
+    If dependencies are healthy but no organization-eligible executable
+    directions match oracle quoteable pair sides, the response contains an empty
+    `directions` array. Oracle or gateway/route registry dependency failures are
+    returned as errors and are not converted to oracle-only or empty successful
+    responses.
+  operationId: paymentsFXDirections
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  responses:
+    '200':
+      description: Organization-level directed FX availability
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/FXDirectionsData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '412':
+      description: Dependency precondition failed
+      content:
+        application/json:
+          schema:
+            $ref: ../response/response.yaml#/components/schemas/ErrorResponse
+    '503':
+      $ref: ../response/operation.yaml#/components/responses/ServiceUnavailable

backend/contracts/sendico/api/payments/immediate.yaml

@@ -0,0 +1,48 @@
+post:
+  tags: [Payments]
+  summary: Initiate payment from immediate intent
+  description: |
+    Creates quote and executes a single payment in one call (request must include `intent`). For
+    raw `card` destinations, execution requires `exp_month` and `exp_year`; `cardToken`
+    destinations only require `token`. Card-recipient AML screening occurs during execution.
+    An unchanged payment reuses its persisted compliance decision on idempotent execution replay,
+    avoiding a duplicate AML call. A definitive denial terminates the payment with public
+    `failureCode: failure_restriction` and `failureReason: aml_denied`.
+  operationId: paymentsInitiateImmediate
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  requestBody:
+    required: true
+    content:
+      application/json:
+        schema:
+          allOf:
+            - $ref: ./request/payment.yaml#/components/schemas/InitiatePaymentRequest
+            - type: object
+              required:
+                - intent
+              not:
+                required:
+                  - quoteRef
+  responses:
+    '200':
+      description: Payment initiated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/PaymentData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/list.yaml

@@ -0,0 +1,76 @@
+get:
+  tags: [Payments]
+  summary: List payments in organization
+  description: |
+    Returns organization payments with cursor pagination and optional filters.
+    State filters accept aliases (`accepted`, `settled`, `failed`, etc.) or canonical orchestration states.
+  operationId: paymentsList
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/cursor.yaml#/components/parameters/Cursor
+    - $ref: ../parameters/limit.yaml#/components/parameters/Limit
+    - name: quotation_ref
+      in: query
+      required: false
+      description: Filter by quotation reference used for execution.
+      schema:
+        type: string
+    - name: quote_ref
+      in: query
+      required: false
+      description: Alias of `quotation_ref`.
+      schema:
+        type: string
+    - name: created_from
+      in: query
+      required: false
+      description: Include payments created at or after this RFC3339 timestamp.
+      schema:
+        type: string
+        format: date-time
+    - name: createdFrom
+      in: query
+      required: false
+      description: Alias of `created_from`.
+      schema:
+        type: string
+        format: date-time
+    - name: created_to
+      in: query
+      required: false
+      description: Include payments created before this RFC3339 timestamp (must be after `created_from`).
+      schema:
+        type: string
+        format: date-time
+    - name: createdTo
+      in: query
+      required: false
+      description: Alias of `created_to`.
+      schema:
+        type: string
+        format: date-time
+    - $ref: ../parameters/state.yaml#/components/parameters/State
+    - $ref: ../parameters/states.yaml#/components/parameters/States
+    - $ref: ../parameters/filter_states.yaml#/components/parameters/FilterStates
+  responses:
+    '200':
+      description: Payments list
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/PaymentsData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/multiquote.yaml

@@ -0,0 +1,37 @@
+post:
+  tags: [Payments]
+  summary: Quote multiple payment intents
+  description: |
+    Calculates a batch quote for multiple payment intents in one request. Each item includes
+    `executable`, `state`, and optional `blockReason` so callers can skip blocked items. Raw
+    `card` destinations can omit expiry while quoting, but quoted items intended for later
+    execution should include `exp_month` and `exp_year`. Card-recipient AML screening is not
+    performed during quotation; it runs during payment execution, so an executable quote does
+    not guarantee AML acceptance.
+  operationId: paymentsMultiQuote
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  requestBody:
+    $ref: ./bodies/payment.yaml#/components/requestBodies/QuotePaymentsBody
+  responses:
+    '200':
+      description: Quotes generated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/PaymentQuotesData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/object.yaml

@@ -0,0 +1,31 @@
+get:
+  tags: [Payments]
+  summary: Get payment by reference
+  description: Returns a single payment by `payments_ref`.
+  operationId: paymentsGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/payments_ref.yaml#/components/parameters/PaymentsRef
+  responses:
+    '200':
+      description: Payment data
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/PaymentData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/quote.yaml

@@ -0,0 +1,37 @@
+post:
+  tags: [Payments]
+  summary: Quote single payment intent
+  description: |
+    Calculates quote for one payment intent without executing payment. The response includes
+    `quote.executable`, `quote.state`, and optional `quote.blockReason` so clients can reject
+    non-executable quotes before attempting execution. Raw `card` destinations can omit expiry
+    while quoting, but quotes intended for later execution should include `exp_month` and
+    `exp_year`. Card-recipient AML screening is not performed during quotation; it runs during
+    payment execution, so an executable quote does not guarantee AML acceptance.
+  operationId: paymentsQuote
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  requestBody:
+    $ref: ./bodies/payment.yaml#/components/requestBodies/QuotePaymentBody
+  responses:
+    '200':
+      description: Quote generated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/payment.yaml#/components/schemas/PaymentQuoteData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/registry.yaml

@@ -0,0 +1,30 @@
+get:
+  tags: [Payments]
+  summary: Get discovery registry snapshot for payments dependencies
+  description: Returns the latest discovery lookup payload used by payments integrations.
+  operationId: paymentsRegistryList
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  responses:
+    '200':
+      description: Discovery registry payload
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    type: object
+                    additionalProperties: true
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/registry_refresh.yaml

@@ -0,0 +1,32 @@
+get:
+  tags: [Payments]
+  summary: Get latest discovery refresh event for payments dependencies
+  description: Returns the latest refresh event consumed by the payments API.
+  operationId: paymentsRegistryRefreshGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  responses:
+    '200':
+      description: Discovery refresh payload
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    type:
+                      - object
+                      - 'null'
+                    additionalProperties: true
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/payments/request/payment.yaml

@@ -0,0 +1,163 @@
+components:
+  schemas:
+    PaymentBase:
+      description: Base fields shared by payment initiation request payloads.
+      type: object
+      additionalProperties: false
+      required:
+        - idempotencyKey
+      properties:
+        idempotencyKey:
+          description: Client-supplied key used to safely deduplicate requests.
+          type: string
+        metadata:
+          description: Optional request metadata forwarded through payment processing.
+          type: object
+          additionalProperties:
+            type: string
+
+    QuotePaymentRequest:
+      description: |
+        Request payload to quote a single payment intent.
+        For raw `card` destinations, quotation only requires `pan`.
+        If the quoted payment may later be executed, include `exp_month` and `exp_year` during quotation because execution reuses the quoted endpoint snapshot.
+      type: object
+      additionalProperties: false
+      required:
+        - intent
+      properties:
+        idempotencyKey:
+          description: Idempotency key used when persisting quote context.
+          type: string
+        metadata:
+          description: Optional metadata associated with the quote request.
+          type: object
+          additionalProperties:
+            type: string
+        clientPaymentRef:
+          description: Optional caller-side payment correlation reference to persist with the quote and reuse during execution when the execute request omits it.
+          type: string
+        intent:
+          description: Payment intent to be priced. See `PaymentIntent.destination` for raw-card quote versus execution requirements.
+          $ref: ../../../models/payment/payment.yaml#/components/schemas/PaymentIntent
+        previewOnly:
+          description: If true, returns a preview quote without requiring idempotency.
+          type: boolean
+      allOf:
+        - if:
+            properties:
+              previewOnly:
+                const: true
+            required:
+              - previewOnly
+          then:
+            not:
+              required:
+                - idempotencyKey
+          else:
+            required:
+              - idempotencyKey
+
+    QuotePaymentsRequest:
+      description: |
+        Request payload to quote multiple payment intents in a single call.
+        For raw `card` destinations, quotation only requires `pan`.
+        If quoted items may later be executed, include `exp_month` and `exp_year` during quotation because execution reuses the quoted endpoint snapshot.
+      type: object
+      additionalProperties: false
+      required:
+        - intents
+      properties:
+        idempotencyKey:
+          description: Idempotency key used when persisting batch quote context.
+          type: string
+        metadata:
+          description: Optional metadata associated with the quote request.
+          type: object
+          additionalProperties:
+            type: string
+        clientPaymentRef:
+          description: Optional caller-side batch payment correlation reference to persist with the quote and reuse during execution when the execute request omits it.
+          type: string
+        intents:
+          description: List of payment intents to be priced. See each intent destination for raw-card quote versus execution requirements.
+          type: array
+          minItems: 1
+          items:
+            $ref: ../../../models/payment/payment.yaml#/components/schemas/PaymentIntent
+        previewOnly:
+          description: If true, returns preview quotes without requiring idempotency.
+          type: boolean
+      allOf:
+        - if:
+            properties:
+              previewOnly:
+                const: true
+            required:
+              - previewOnly
+          then:
+            not:
+              required:
+                - idempotencyKey
+          else:
+            required:
+              - idempotencyKey
+
+    InitiatePaymentRequest:
+      description: |
+        Request payload to initiate a single payment.
+        When executing a raw `card` destination from inline `intent`, `pan`, `exp_month`, and `exp_year` must be present.
+        When executing a `cardToken` destination, only `token` is required by current logic.
+      allOf:
+        - $ref: ./payment.yaml#/components/schemas/PaymentBase
+        - type: object
+          additionalProperties: false
+          oneOf:
+            - required: [intent]
+            - required: [quoteRef]
+          properties:
+            intent:
+              description: Payment intent to execute directly. Raw `card` destinations require expiry at execution time.
+              $ref: ../../../models/payment/payment.yaml#/components/schemas/PaymentIntent
+            quoteRef:
+              description: Reference to a previously generated quote to execute. If that quote contains a raw `card` destination, the original quote must already include `exp_month` and `exp_year`.
+              type: string
+            clientPaymentRef:
+              description: Optional caller-side payment correlation reference. When omitted, execution may reuse the value stored with the quote.
+              type: string
+
+    InitiatePaymentsRequest:
+      description: |
+        Request payload to initiate multiple payments from a multi-quote reference.
+        If any quoted item contains a raw `card` destination, that item's original quote must already include `exp_month` and `exp_year`.
+      allOf:
+        - $ref: ./payment.yaml#/components/schemas/PaymentBase
+        - type: object
+          additionalProperties: false
+          required:
+            - quoteRef
+          properties:
+            quoteRef:
+              description: Reference to a previously generated multi-quote. Raw-card items execute from the stored quoted endpoint snapshot.
+              type: string
+            clientPaymentRef:
+              description: Optional caller-side payment correlation reference. When omitted, execution may reuse the value stored with the quote.
+              type: string
+
+    InitiatePaymentByQuoteRequest:
+      description: |
+        Request payload to initiate one payment from an existing quote reference.
+        If the quote contains a raw `card` destination, the original quote must already include `exp_month` and `exp_year`.
+      allOf:
+        - $ref: ./payment.yaml#/components/schemas/PaymentBase
+        - type: object
+          additionalProperties: false
+          required:
+            - quoteRef
+          properties:
+            quoteRef:
+              description: Reference to a previously generated quote to execute. Execution reuses the stored quoted endpoint snapshot.
+              type: string
+            clientPaymentRef:
+              description: Optional caller-side payment correlation reference. When omitted, execution may reuse the value stored with the quote.
+              type: string

backend/contracts/sendico/api/payments/response/payment.yaml

@@ -0,0 +1,114 @@
+components:
+  schemas:
+    PaymentQuoteData:
+      description: Response payload for a single payment quote.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - quote
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        idempotencyKey:
+          description: Idempotency key associated with the quote response.
+          type: string
+        clientPaymentRef:
+          description: Caller-supplied payment correlation reference echoed from the quote request, when provided.
+          type: string
+        quote:
+          description: Generated quote data for the requested payment intent.
+          $ref: ../../../models/payment/payment.yaml#/components/schemas/PaymentQuote
+
+    PaymentQuotesData:
+      description: Response payload for a batch quote request.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - quote
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        quote:
+          description: Batch quote summary and quoted items.
+          type: object
+          additionalProperties: false
+          properties:
+            idempotencyKey:
+              description: Idempotency key associated with the batch quote response.
+              type: string
+            clientPaymentRef:
+              description: Caller-supplied payment correlation reference echoed from the batch quote request, when provided.
+              type: string
+            quoteRef:
+              description: Reference to the generated batch quote.
+              type: string
+            items:
+              description: Collection of quotes for each requested payment intent.
+              type: array
+              items:
+                $ref: ../../../models/payment/payment.yaml#/components/schemas/PaymentQuote
+
+    PaymentsData:
+      description: Response payload containing a list of payments.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - payments
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        payments:
+          description: Collection of payment records.
+          type: array
+          items:
+            $ref: ../../../models/payment/payment.yaml#/components/schemas/Payment
+        page:
+          description: Pagination cursor metadata for payment listing endpoints.
+          $ref: ../../../models/common/pagination.yaml#/components/schemas/CursorPageResponse
+
+    PaymentData:
+      description: Response payload containing a single payment record.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - payment
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        payment:
+          description: Requested payment record.
+          $ref: ../../../models/payment/payment.yaml#/components/schemas/Payment
+
+    FXCurrenciesData:
+      description: Response payload containing the BFF startup-cached Treasury FX currency catalogue projection.
+      type: object
+      additionalProperties: false
+      required:
+        - currencies
+      properties:
+        currencies:
+          description: Client-visible currencies backed by Treasury Currency Catalog metadata.
+          type: array
+          items:
+            $ref: ../../../models/payment/fx_metadata.yaml#/components/schemas/FXCurrency
+
+    FXDirectionsData:
+      description: Response payload containing organization-level directed FX availability.
+      type: object
+      additionalProperties: false
+      required:
+        - directions
+      properties:
+        directions:
+          description: Directions with at least one eligible direction-level route for the organization.
+          type: array
+          items:
+            $ref: ../../../models/payment/fx_metadata.yaml#/components/schemas/FXDirection

backend/contracts/sendico/api/recipients/archive.yaml

@@ -0,0 +1,37 @@
+get:
+  tags: [Recipients]
+  summary: Archive/unarchive recipient
+  description: Sets recipient archive state by `recipients_ref` and required `archived` query parameter.
+  operationId: recipientsArchive
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/org_ref.yaml#/components/parameters/OrgRef
+    - $ref: ../parameters/recipients_ref.yaml#/components/parameters/RecipientsRef
+    - name: archived
+      in: query
+      required: true
+      description: Target archive value to set on the recipient.
+      schema:
+        type: boolean
+    - $ref: ../parameters/cascade.yaml#/components/parameters/Cascade
+  responses:
+    '200':
+      description: Archive state updated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/recipient.yaml#/components/schemas/RecipientsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/recipients/bodies/recipient.yaml

@@ -0,0 +1,17 @@
+components:
+  requestBodies:
+    RecipientCreateBody:
+      description: JSON body containing recipient details for create.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/recipient.yaml#/components/schemas/RecipientCreateRequest
+
+    RecipientUpdateBody:
+      description: JSON body containing recipient details for update.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/recipient.yaml#/components/schemas/RecipientUpdateRequest

backend/contracts/sendico/api/recipients/create.yaml

@@ -0,0 +1,33 @@
+post:
+  tags: [Recipients]
+  summary: Create recipient
+  description: Creates a recipient inside the organization identified by `org_ref`.
+  operationId: recipientsCreate
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/org_ref.yaml#/components/parameters/OrgRef
+  requestBody:
+    $ref: ./bodies/recipient.yaml#/components/requestBodies/RecipientCreateBody
+  responses:
+    '201':
+      description: Recipient created
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/recipient.yaml#/components/schemas/RecipientsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/recipients/list.yaml

@@ -0,0 +1,36 @@
+get:
+  tags: [Recipients]
+  summary: List recipients
+  description: |
+    Returns recipients for the specified organization context.
+    Supports offset pagination and optional archive filtering.
+    The route currently includes both `org_ref` and `organizations_ref`; the handler resolves organization context from `org_ref` and ignores `organizations_ref`.
+  operationId: recipientsList
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/org_ref.yaml#/components/parameters/OrgRef
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+    - $ref: ../parameters/limit.yaml#/components/parameters/Limit
+    - $ref: ../parameters/offset.yaml#/components/parameters/Offset
+    - $ref: ../parameters/archived.yaml#/components/parameters/Archived
+  responses:
+    '200':
+      description: Recipient list
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/recipient.yaml#/components/schemas/RecipientsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/recipients/object.yaml

@@ -0,0 +1,64 @@
+get:
+  tags: [Recipients]
+  summary: Get recipient by reference
+  description: Returns a recipient by `recipients_ref`.
+  operationId: recipientsGet
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/recipients_ref.yaml#/components/parameters/RecipientsRef
+  responses:
+    '200':
+      description: Recipient data
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/recipient.yaml#/components/schemas/RecipientsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError
+
+delete:
+  tags: [Recipients]
+  summary: Delete recipient
+  description: Deletes recipient by reference. Use `cascade=true` to remove dependent objects when supported.
+  operationId: recipientsDelete
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/recipients_ref.yaml#/components/parameters/RecipientsRef
+    - $ref: ../parameters/cascade.yaml#/components/parameters/Cascade
+  responses:
+    '200':
+      description: Recipient deleted
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/recipient.yaml#/components/schemas/RecipientsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/recipients/request/recipient.yaml

@@ -0,0 +1,53 @@
+components:
+  schemas:
+    RecipientBaseRequest:
+      type: object
+      additionalProperties: false
+      properties:
+        id:
+          description: Optional recipient identifier. Required by the current update handler.
+          $ref: ../../../models/objectid.yaml#/components/schemas/ObjectId
+        name:
+          description: Optional human-readable recipient name.
+          type: string
+        description:
+          description: Optional free-form recipient description.
+          type: string
+          nullable: true
+        email:
+          description: Optional recipient email address.
+          type: string
+          format: email
+        avatarUrl:
+          description: Optional avatar URL.
+          type: string
+          nullable: true
+        status:
+          description: Optional recipient status. When omitted, current handler behavior falls back to the model zero value (`ready`).
+          type: string
+          enum:
+            - ready
+            - registered
+            - notRegistered
+        type:
+          description: Optional recipient type. When omitted, current handler behavior falls back to the model zero value (`internal`).
+          type: string
+          enum:
+            - internal
+            - external
+
+    RecipientCreateRequest:
+      description: |
+        Request payload used to create a recipient.
+        The current create handler does not require any JSON fields beyond a valid object payload; organization context comes from the `org_ref` path parameter.
+      allOf:
+        - $ref: '#/components/schemas/RecipientBaseRequest'
+
+    RecipientUpdateRequest:
+      description: |
+        Request payload used to update a recipient.
+        The current PUT handler targets the record by `id` and then replaces it with the submitted values; omitted fields may therefore be reset to zero values.
+      required:
+        - id
+      allOf:
+        - $ref: '#/components/schemas/RecipientBaseRequest'

backend/contracts/sendico/api/recipients/response/recipient.yaml

@@ -0,0 +1,18 @@
+components:
+  schemas:
+    RecipientsAuthData:
+      description: Authenticated response payload containing recipients.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - recipients
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        recipients:
+          description: Collection of recipients available to the authenticated account.
+          type: array
+          items:
+            $ref: ../../../models/recipient/recipient.yaml#/components/schemas/Recipient

backend/contracts/sendico/api/recipients/update.yaml

@@ -0,0 +1,31 @@
+put:
+  tags: [Recipients]
+  summary: Update recipient
+  description: Updates recipient fields from request payload. The current handler requires `id`; omitted fields may be replaced with zero values.
+  operationId: recipientsUpdate
+  security:
+    - bearerAuth: []
+  requestBody:
+    $ref: ./bodies/recipient.yaml#/components/requestBodies/RecipientUpdateBody
+  responses:
+    '200':
+      description: Recipient updated
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/recipient.yaml#/components/schemas/RecipientsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/response/error.yaml

@@ -0,0 +1,24 @@
+components:
+  schemas:
+    ApiError:
+      description: Standard API error envelope with optional debugging details.
+      type: object
+      additionalProperties: false
+      required:
+        - code
+        - error
+        - source
+      properties:
+        code:
+          description: Application-specific numeric error code.
+          type: integer
+          format: int32
+        error:
+          description: Human-readable error summary.
+          type: string
+        source:
+          description: Component or subsystem that produced the error.
+          type: string
+        details:
+          description: Optional detailed message providing additional failure context.
+          type: string

backend/contracts/sendico/api/response/operation.yaml

@@ -0,0 +1,85 @@
+components:
+  responses:
+    Ok:
+      description: Successful response
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/BaseResponse
+
+    Created:
+      description: Resource created
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/BaseResponse
+
+    Accepted:
+      description: Request accepted for processing
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/BaseResponse
+
+    BadRequest:
+      description: Bad request payload or query/path parameter
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    Unauthorized:
+      description: Unauthorized
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    Forbidden:
+      description: Forbidden
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    NotFound:
+      description: Resource not found
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    Gone:
+      description: Resource is no longer available
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    Conflict:
+      description: Conflict
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    TooManyRequests:
+      description: Too many requests
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    ServiceUnavailable:
+      description: Service unavailable
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse
+
+    InternalServerError:
+      description: Internal server error
+      content:
+        application/json:
+          schema:
+            $ref: ./response.yaml#/components/schemas/ErrorResponse

backend/contracts/sendico/api/response/response.yaml

@@ -0,0 +1,47 @@
+components:
+  schemas:
+    BaseResponse:
+      type: object
+      additionalProperties: false
+      required:
+        - status
+        - data
+      properties:
+        status:
+          $ref: ./status.yaml#/components/schemas/ApiStatus
+        data:
+          description: Payload for success or error responses.
+
+    ErrorResponse:
+      allOf:
+        - $ref: ./response.yaml#/components/schemas/BaseResponse
+        - type: object
+          properties:
+            status:
+              type: string
+              enum:
+                - error
+            data:
+              $ref: ./error.yaml#/components/schemas/ApiError
+
+    SuccessResultData:
+      type: object
+      additionalProperties: false
+      required:
+        - result
+      properties:
+        result:
+          type: boolean
+
+    SuccessResultResponse:
+      allOf:
+        - $ref: ./response.yaml#/components/schemas/BaseResponse
+        - type: object
+          properties:
+            status:
+              type: string
+              enum:
+                - success
+                - processed
+            data:
+              $ref: ./response.yaml#/components/schemas/SuccessResultData

backend/contracts/sendico/api/response/status.yaml

@@ -0,0 +1,10 @@
+components:
+  schemas:
+    ApiStatus:
+      type: string
+      description: Unified response status used by backend wrappers.
+      enum:
+        - success
+        - processed
+        - error
+        - request

backend/contracts/sendico/api/verification/bodies/verification.yaml

@@ -0,0 +1,17 @@
+components:
+  requestBodies:
+    VerificationCodeBody:
+      description: JSON payload used to request a new verification code.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/verification.yaml#/components/schemas/VerificationCodeRequest
+
+    VerifyCodeBody:
+      description: JSON payload containing a verification code to validate.
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: ../request/verification.yaml#/components/schemas/CodeVerificationRequest

backend/contracts/sendico/api/verification/create.yaml

@@ -0,0 +1,37 @@
+post:
+  tags: [Verification, Auth]
+  summary: Request verification code
+  description: |
+    Creates a verification challenge for the specified purpose/target.
+    For `purpose=login`, request must be authorized with a pending account token.
+  operationId: verificationRequestCode
+  security:
+    - bearerAuth: []
+  requestBody:
+    $ref: ./bodies/verification.yaml#/components/requestBodies/VerificationCodeBody
+  responses:
+    '202':
+      description: Verification code requested
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/verification.yaml#/components/schemas/VerificationResponseData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '429':
+      $ref: ../response/operation.yaml#/components/responses/TooManyRequests
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/verification/request/verification.yaml

@@ -0,0 +1,73 @@
+components:
+  schemas:
+    VerificationCodeRequest:
+      type: object
+      additionalProperties: false
+      required:
+        - purpose
+      properties:
+        purpose:
+          type: string
+          description: Verification purpose, e.g. login.
+        target:
+          type: string
+          format: email
+          description: Optional destination override. When omitted, current handler falls back to the authenticated account email/login.
+        idempotencyKey:
+          type: string
+        quoteRef:
+          description: Required when `purpose` is `payout`; omitted for login and other verification purposes.
+          type: string
+      allOf:
+        - if:
+            properties:
+              purpose:
+                const: payout
+            required:
+              - purpose
+          then:
+            required:
+              - quoteRef
+
+    CodeVerificationRequest:
+      type: object
+      additionalProperties: false
+      required:
+        - purpose
+        - code
+      properties:
+        purpose:
+          type: string
+          description: Verification purpose, e.g. login.
+        target:
+          type: string
+          format: email
+          description: Optional destination override. When omitted, current handler falls back to the authenticated account email/login.
+        idempotencyKey:
+          type: string
+        quoteRef:
+          description: Required when `purpose` is `payout`; omitted for login and other verification purposes.
+          type: string
+        code:
+          type: string
+        sessionIdentifier:
+          $ref: ../../../models/auth/session_identifier.yaml#/components/schemas/SessionIdentifier
+      allOf:
+        - if:
+            properties:
+              purpose:
+                const: login
+            required:
+              - purpose
+          then:
+            required:
+              - sessionIdentifier
+        - if:
+            properties:
+              purpose:
+                const: payout
+            required:
+              - purpose
+          then:
+            required:
+              - quoteRef

backend/contracts/sendico/api/verification/resend.yaml

@@ -0,0 +1,37 @@
+post:
+  tags: [Verification, Auth]
+  summary: Resend verification code
+  description: |
+    Re-issues a verification challenge using the same request shape as `/verification`.
+    Cooldown and retry limits are enforced by backend verification storage policy.
+  operationId: verificationResendCode
+  security:
+    - bearerAuth: []
+  requestBody:
+    $ref: ./bodies/verification.yaml#/components/requestBodies/VerificationCodeBody
+  responses:
+    '202':
+      description: Verification code resent
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/verification.yaml#/components/schemas/VerificationResponseData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '429':
+      $ref: ../response/operation.yaml#/components/responses/TooManyRequests
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/verification/response/verification.yaml

@@ -0,0 +1,35 @@
+components:
+  schemas:
+    VerificationResponseData:
+      description: Response data returned after requesting a verification code.
+      type: object
+      additionalProperties: false
+      required:
+        - idempotencyKey
+        - ttl_seconds
+        - cooldown_seconds
+        - target
+      properties:
+        idempotencyKey:
+          description: Idempotency key associated with the verification request.
+          type: string
+        ttl_seconds:
+          description: Verification code validity period in seconds.
+          type: integer
+          format: int32
+        cooldown_seconds:
+          description: Cooldown period before another code can be requested.
+          type: integer
+          format: int32
+        target:
+          description: Destination where the verification code was sent.
+          type: string
+        quoteRef:
+          description: Payment quote reference echoed for payout verification requests.
+          type: string
+
+    VerifyResultData:
+      description: Result payload returned after code verification succeeds.
+      oneOf:
+        - $ref: ../../accounts/response/auth.yaml#/components/schemas/LoginData
+        - $ref: ../../response/response.yaml#/components/schemas/SuccessResultData

backend/contracts/sendico/api/verification/verify.yaml

@@ -0,0 +1,37 @@
+post:
+  tags: [Verification, Auth]
+  summary: Verify code and complete pending flow
+  description: |
+    Verifies submitted code and consumes verification token.
+    For login purpose, returns full auth payload (access + refresh tokens); for other purposes returns operation result.
+  operationId: verificationVerifyCode
+  security:
+    - bearerAuth: []
+  requestBody:
+    $ref: ./bodies/verification.yaml#/components/requestBodies/VerifyCodeBody
+  responses:
+    '200':
+      description: Verification successful
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/verification.yaml#/components/schemas/VerifyResultData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '404':
+      $ref: ../response/operation.yaml#/components/responses/NotFound
+    '410':
+      $ref: ../response/operation.yaml#/components/responses/Gone
+    '409':
+      $ref: ../response/operation.yaml#/components/responses/Conflict
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/wallets/assets.yaml

@@ -0,0 +1,35 @@
+get:
+  tags: [Wallets]
+  summary: List live managed-wallet assets
+  description: |
+    Returns the live wallet asset catalogue currently announced by healthy CRYPTO
+    gateways in discovery. The endpoint is authenticated and authorized by
+    `organizations_ref`, but the returned asset list is gateway-driven rather than
+    organization-customized. Malformed gateway asset announcements are skipped.
+    If discovery is available but no valid wallet assets are currently announced,
+    the response contains an empty `assets` array.
+  operationId: walletAssetsList
+  security:
+    - bearerAuth: []
+  parameters:
+    - $ref: ../parameters/organizations_ref.yaml#/components/parameters/OrganizationsRef
+  responses:
+    '200':
+      description: Live managed-wallet asset catalogue
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: ../response/response.yaml#/components/schemas/BaseResponse
+              - type: object
+                properties:
+                  data:
+                    $ref: ./response/wallet.yaml#/components/schemas/WalletAssetsAuthData
+    '400':
+      $ref: ../response/operation.yaml#/components/responses/BadRequest
+    '401':
+      $ref: ../response/operation.yaml#/components/responses/Unauthorized
+    '403':
+      $ref: ../response/operation.yaml#/components/responses/Forbidden
+    '500':
+      $ref: ../response/operation.yaml#/components/responses/InternalServerError

backend/contracts/sendico/api/wallets/response/wallet.yaml

@@ -0,0 +1,18 @@
+components:
+  schemas:
+    WalletAssetsAuthData:
+      description: Authenticated response payload containing live wallet assets.
+      type: object
+      additionalProperties: false
+      required:
+        - accessToken
+        - assets
+      properties:
+        accessToken:
+          description: Refreshed access token to be used in subsequent API calls.
+          $ref: ../../../models/auth/token_data.yaml#/components/schemas/TokenData
+        assets:
+          description: Managed-wallet assets currently announced by healthy CRYPTO gateways.
+          type: array
+          items:
+            $ref: ../../../models/wallet/wallet_asset.yaml#/components/schemas/WalletAsset

backend/contracts/sendico/external/chain_network.yaml

@@ -0,0 +1,10 @@
+components:
+  schemas:
+    ChainNetwork:
+      type: string
+      enum:
+        - unspecified
+        - ethereum_mainnet
+        - arbitrum_one
+        - tron_mainnet
+        - tron_nile

backend/contracts/sendico/external/endpoint_type.yaml

@@ -0,0 +1,15 @@
+components:
+  schemas:
+    EndpointType:
+      type: string
+      enum:
+        - paymentMethod
+        - account
+        - recipient
+        - ledger
+        - managedWallet
+        - cryptoAddress
+        - card
+        - cardToken
+        - bankAccount
+        - iban

backend/contracts/sendico/external/fx_side.yaml

@@ -0,0 +1,7 @@
+components:
+  schemas:
+    FxSide:
+      type: string
+      enum:
+        - buy_base_sell_quote
+        - sell_base_buy_quote

backend/contracts/sendico/external/payment_kind.yaml

@@ -0,0 +1,8 @@
+components:
+  schemas:
+    PaymentKind:
+      type: string
+      enum:
+        - payout
+        - internal_transfer
+        - fx_conversion

backend/contracts/sendico/external/payment_method_type.yaml

@@ -0,0 +1,12 @@
+components:
+  schemas:
+    PaymentMethodType:
+      type: string
+      enum:
+        - iban
+        - card
+        - cardToken
+        - bankAccount
+        - wallet
+        - cryptoAddress
+        - ledger