Sinbad Partner API

curl -X PATCH https://us-central1-sinbad-staging-env.cloudfunctions.net/b2b-v1/v1/trades/trade_demo/proof \
     -H "Authorization: Bearer <token>" \
     -H "Content-Type: application/json" \
     -d '{
  "contentType": "image/png",
  "dataBase64": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+/lS8AAAAASUVORK5CYII=",
  "expectedProofId": "proof_previous"
}'

{
  "proofId": "proof_demo",
  "contentType": "image/png",
  "size": 68,
  "uploadedByRole": "customer",
  "uploadedAt": "2026-10-23T10:00:00.000Z",
  "base64": "/9j/2wBDABQODxIPDRQSEBIXFRQYHjIhHhwcHj0sLiQySUBMS0dARkVQWnNiUFVtVkVGZIhlbXd7gYKBTmCNl4x9lnN+gXz/2wBDARUXFx4aHjshITt8U0ZTfHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHx8fHz/wAARCABAAEADASIAAhEBAxEB/8QAFQABAQAAAAAAAAAAAAAAAAAAAAb/xAAUEAEAAAAAAAAAAAAAAAAAAAAA/8QAFAEBAAAAAAAAAAAAAAAAAAAAAP/EABQRAQAAAAAAAAAAAAAAAAAAAAD/2gAMAwEAAhEDEQA/ALMAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH/2Q==",
  "width": 1,
  "height": 1
}

Replace payment proof.

Credential: Customer session

Before you call

A customer session for the same partner, integration, customer, wallet and chain.
To change proof, the customer must be the fiat payer on a BUY, and the trade must be CREATED, PAID or DISPUTED.
Uploads accept PNG or JPEG files up to 3 MiB decoded. Authenticated reads return merchant originals unchanged.

BUY customer payer only while CREATED, PAID or DISPUTED. Save the new file before replacing the active receipt; failed uploads retain the prior proof. Stale expectedProofId returns 409. An identical replacement retry returns the saved proof. Chat history retains previous receipt files.

Storage unavailability can return 502 or 503 UPSTREAM_ERROR. Retry with backoff; contact Sinbad with requestId if it persists.

Confirm with Sinbad that this endpoint is enabled in your environment.

Errors

Status	Code	What to do
400	`VALIDATION_ERROR`	Correct the fields reported in details before retrying.
401	`UNAUTHENTICATED`	Create a new customer session or use a valid server credential.
403	`FORBIDDEN`	Check credential ownership, integration and the supplied Origin.
404	`NOT_FOUND`	Check the resource ID. A resource that belongs to someone else also returns 404.
409	`CONFLICT`	Read the current state again before you prepare or retry.
502	`UPSTREAM_ERROR`	Retry with backoff and quote requestId if it persists. For transaction reports, retry the same hash without sending another transaction.
503	`UPSTREAM_ERROR`	Retry with backoff; preserve the same idempotency key for a repeated mutation.

Authentication

AuthorizationBearer

Bearer authentication of the form Bearer <token>, where token is your auth token.

Path parameters

tradeIdstringRequired

Request

This endpoint expects an object.

contentTypeenumRequired

Allowed values:

dataBase64stringRequiredformat: "byte"1-4194304 characters

expectedProofIdstringRequiredformat: "^[A-Za-z0-9_-]{1,128}$"

Response

Replacement proof metadata with a new proofId and image preview.

proofIdstring

contentTypestring

Original content type; merchant files can use native image formats.

sizeinteger>=1

uploadedByRoleenum

Allowed values:

uploadedAtdatetime or null

base64string

Blurred preview, not original file bytes.

widthdouble>=0

heightdouble>=0

Errors

400

Bad Request Error

401

Unauthorized Error

403

Forbidden Error

404

Not Found Error

409

Conflict Error

502

Bad Gateway Error

503

Service Unavailable Error