Records a payment against an invoice and applies it immediately.

POST /accounting/invoices/{id}/pay

Group: Accounting › Invoices · Operation ID: payInvoice

Records a payment against one invoice and applies it immediately. The invoice is named by the :id path segment. The response contains the id of the payment created.

This is a settlement, not a bookkeeping note. A payment record is created against the invoice's customer and entity, applied to the invoice, and posted to the ledger against the entity's default receivable account. Read the invoice back with GET accounting/invoices/:id to see the reduced totalAmountDue and the increased paymentsApplied, or read the payment with GET accounting/payments/:id.

The amount is in the invoice's currency and must be greater than zero. An over-payment is refused with AMOUNT_EXCEEDS_DUE, whose details contain the amount still outstanding. A partial payment is accepted and is the normal case for installments. Call the endpoint again for each one.

bankFeeAmount is what the bank or processor deducted. It is recorded on the payment rather than subtracted from it. Send the gross amount the customer paid in amount, and the fee beside it.

Send an Idempotency-Key header. A retry carrying the same key and body replays the original response instead of recording a second payment, so a timed-out call is safe to retry. Without the header, a retried call that had in fact succeeded records a second payment.

The call runs in one transaction. A failure writes neither the payment nor its application.

Open in the interactive reference

Parameters

Name In Type Required Description
Api-Version header "v1" yes The API version this request targets, named by its public identifier. Required on every request; omitting it, or naming a version this company does not have, is answered with 400. This document describes version v1.
Idempotency-Key header string no An opaque caller-chosen string (1-255 characters) that makes this request safe to retry. Repeating the same key with an identical request body replays the original response instead of re-executing - but only once that original request succeeded; a failed attempt re-executes on retry. Repeating the key with a different body is answered with 422. A key still in flight is answered with 409 - as is a key whose original request was interrupted before it finished, for a few minutes afterwards, until that attempt is presumed dead. A completed response stays replayable for 24 hours. The key is scoped to the caller, not to the action: reusing it for a different action is answered with 409 or 422 rather than treated independently. On read actions this header is ignored. On write actions that cannot offer the guarantee it is answered with 400 IDEMPOTENCY_NOT_SUPPORTED rather than silently ignored.
id path string yes The unique identifier for the invoice to settle.

Request body

Required, application/json: payInvoiceInput.

Field Type Required Description
amount string (decimal) yes The amount paid, in the invoice's currency. Must be greater than zero and may not exceed the amount still due.
paymentDate string (date) yes The date the payment was received or settled. Format YYYY-MM-DD. It drives the ledger posting and the reporting period.
paymentType string, one of "check", "ach", "wire", "creditCard", "directDebit", "sepaCreditTransfer" yes How the payment was tendered.
paymentNote string no A free-text note recorded on the payment, for example a bank reference or check number.
bankFeeAmount string (decimal) no The fee the bank or processor deducted, in the invoice's currency. Recorded on the payment rather than subtracted from it. Send the gross amount in amount.

Example:

{
  "amount": "1210.00",
  "paymentDate": "2026-09-15",
  "paymentType": "wire",
  "paymentNote": "Remittance ref 88213",
  "bankFeeAmount": "12.50"
}

Response

200 Success

Under data (payInvoiceOutput):

Field Type Required Description
paymentId string yes The unique identifier for the payment created. Read it back with GET accounting/payments/:id, or re-read the invoice for its updated balance.

Response headers

Errors

Code Status
INVOICE_NOT_FOUND 400
INVALID_AMOUNT 400
AMOUNT_EXCEEDS_DUE 400
IDEMPOTENCY_KEY_CONFLICT 409
IDEMPOTENCY_PAYLOAD_MISMATCH 422

Statuses