> ## Documentation Index > Fetch the complete documentation index at: https://docs.filexpress.app/llms.txt > Use this file to discover all available pages before exploring further. # Register payment > Applies a payment per purchase (`allocations`) or spread from the oldest purchase to the newest; all or nothing. Depending on the payment method, the bank (`bank_id`), the petty cash fund (`petty_cash_id`), or the checkbook (`checkbook_id` + `check_number`) is affected; get their IDs in Treasury. `cost_center_id` (optional) defaults to the document's. **Required permission:** `payables.payments` ## OpenAPI ````yaml /api-reference/openapi.en.json post /payables/payments openapi: 3.0.3 info: title: FileXpress External API version: 1.0.0 description: >- API for integrating third-party systems with FileXpress: billing, HR, accounting, inventory, projects, accounts receivable and payable, treasury, pricing and promotions, and cash. Current base URL: /api/external/v1. The legacy unversioned path (/api/external) will be removed on January 1, 2027; migrate to /api/external/v1 (same endpoints, only the base URL changes). The v2 API (/api/external/v2) exposes currencies and exchange rates, sales and purchases in foreign currency, taxes by id, payrolls with branch, and errors with a stable `code`; its operations carry the /v2 prefix in the path. We suggest migrating to the available v2 routes before March 30, 2027. servers: - url: https://api.filexpress.app/api/external/v1 description: Production security: - ApiKey: [] tags: - name: General - name: Billing · Sales - name: Billing · Purchases - name: Billing · Customers - name: Billing · Suppliers - name: Billing · Products - name: Catalogs - name: HR · Employees - name: HR · Attendance - name: HR · Labor rules - name: HR · Schedules - name: HR · Holidays - name: HR · Attendance results - name: HR · Leave requests - name: HR · Payrolls - name: Accounting - name: Inventory - name: Projects - name: Accounts receivable - name: Accounts payable - name: Treasury - name: Pricing and promotions - name: Cash - name: Points of sale - name: API v2 · General - name: API v2 · Currencies and rates - name: API v2 · Countries - name: API v2 · Sales - name: API v2 · Purchases - name: API v2 · Payrolls paths: /payables/payments: post: tags: - Accounts payable summary: Register payment description: >- Applies a payment per purchase (`allocations`) or spread from the oldest purchase to the newest; all or nothing. Depending on the payment method, the bank (`bank_id`), the petty cash fund (`petty_cash_id`), or the checkbook (`checkbook_id` + `check_number`) is affected; get their IDs in Treasury. `cost_center_id` (optional) defaults to the document's. **Required permission:** `payables.payments` parameters: - $ref: '#/components/parameters/IdempotencyKey' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/PayablePaymentRequest' examples: allocations: summary: Por compra value: payment_method_id: 9d1c5a3e-4b7f-4e2a-9c1d-2f6b8a0e7c11 bank_id: 3b8e2f10-7c4d-4a9e-b1f2-5d6c7e8f9a01 reference_number: TRF-88231 payment_date: '2026-10-06' notes: Pago parcial allocations: - expense_id: 9d1c5a3e-4b7f-4e2a-9c1d-2f6b8a0e7c11 amount: 300 checkbook_id: 9d1c5a3e-4b7f-4e2a-9c1d-2f6b8a0e7c11 check_number: '000123' auto: summary: Reparto automático value: payment_method_id: 9d1c5a3e-4b7f-4e2a-9c1d-2f6b8a0e7c11 payment_date: '2026-10-06' provider_id: 3b8e2f10-7c4d-4a9e-b1f2-5d6c7e8f9a01 branch_id: 9d1c5a3e-4b7f-4e2a-9c1d-2f6b8a0e7c11 amount: 630 responses: '201': description: Payment applied content: application/json: schema: type: object required: - status - data properties: status: type: boolean example: true data: $ref: '#/components/schemas/PayablePaymentResult' example: status: true data: payments: - payment_id: 3b8e2f10-7c4d-4a9e-b1f2-5d6c7e8f9a01 expense_id: 9d1c5a3e-4b7f-4e2a-9c1d-2f6b8a0e7c11 generation_code: A1B2C3D4-0000-4C5D-9E6F-0A1B2C3D4E5F amount: 300 pending_amount: 152 payment_status: partial total_applied: 300 headers: Idempotent-Replayed: $ref: '#/components/headers/IdempotentReplayed' '401': $ref: '#/components/responses/E401' '403': $ref: '#/components/responses/E403' '404': description: Purchase or branch does not exist or belongs to another business content: application/json: schema: $ref: '#/components/schemas/Error' example: status: false message: Bill 9d1c5a3e-4b7f-4e2a-9c1d-2f6b8a0e7c11 not found '409': description: Idempotency conflict content: application/json: schema: $ref: '#/components/schemas/Error' examples: idem_body: summary: Idempotency-Key reutilizada con otro cuerpo value: status: false message: >- This Idempotency-Key was already used with a different request. idem_busy: summary: Petición con la misma llave en proceso value: status: false message: >- A request with this Idempotency-Key is already being processed. '422': description: >- Validation, payment method/bank does not exist, amount greater than the balance, or document already paid content: application/json: schema: $ref: '#/components/schemas/Error' example: status: false message: The amount exceeds the provider pending balance. '429': $ref: '#/components/responses/E429' components: parameters: IdempotencyKey: name: Idempotency-Key in: header required: false description: >- Optional. Unique key per operation (max. 100 characters, valid for 24 h per integration). A retry with the same key and the same body returns the original response (header `Idempotent-Replayed: true`) without repeating the operation; with a different body, or while the first is still in progress, it returns 409. schema: type: string maxLength: 100 example: pago-2026-10-06-000123 schemas: PayablePaymentRequest: type: object properties: payment_method_id: type: string format: uuid description: Payment method (GET /payment-methods). bank_id: type: string format: uuid description: Bank (GET /treasury/banks). cost_center_id: type: string format: uuid description: >- Cost center of the payment (leaf and active; GET /accounting/cost-centers). If missing, that of the document. Only applied to income statement account lines when posting. reference_number: type: string description: Reference (max. 255). payment_date: type: string format: date description: Payment date. notes: type: string description: Notes (max. 500). branch_id: type: string format: uuid description: Required together with the third party (automatic mode). amount: type: number exclusiveMinimum: true minimum: 0 description: Amount to distribute (automatic mode). provider_id: type: string format: uuid description: Supplier (automatic mode, instead of allocations). petty_cash_id: type: string format: uuid description: Petty cash (GET /treasury/petty-cashes). checkbook_id: type: string format: uuid description: Checkbook (GET /treasury/checkbooks). check_number: type: string maxLength: 50 allocations: type: array minItems: 1 maxItems: 200 description: Amount per purchase (or use provider_id). items: type: object properties: expense_id: type: string format: uuid amount: type: number exclusiveMinimum: true minimum: 0 required: - expense_id - amount required: - payment_method_id - payment_date PayablePaymentResult: type: object properties: payments: type: array items: type: object properties: payment_id: type: string format: uuid expense_id: type: string format: uuid generation_code: type: string amount: type: number pending_amount: type: number payment_status: type: string description: Payment status. enum: - partial - payed required: - payment_id - expense_id - amount total_applied: type: number required: - payments - total_applied Error: type: object properties: status: type: boolean example: false message: type: string errors: type: object additionalProperties: type: array items: type: string description: Errors per field (validation only). required: - status - message headers: IdempotentReplayed: description: >- `true` when the response is the replay of a previous request with the same Idempotency-Key. schema: type: string enum: - 'true' responses: E401: description: Missing or invalid API Key content: application/json: example: status: false message: Invalid API Key. E403: description: Integration without the required permission or deactivated content: application/json: example: status: false message: This integration does not have the 'hr.employees' permission. required_scope: hr.employees E429: description: Rate limit exceeded content: application/json: example: status: false message: Rate limit exceeded. Please try again later. rate_limit: 100 securitySchemes: ApiKey: type: apiKey in: header name: X-API-Key description: Integration API Key (Integrations → New Integration). ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.