Upload a payout supporting document
Uploads the supporting document (invoice/receipt) that the US/USD corridor requires on EVERY outbound transfer (ach, wire and swift). Send the raw binary body with its Content-Type (PDF, PNG, JPEG, WEBP, TXT, CSV, DOC(X) or XLS(X), up to 50 MB) and the filename in the name query param. The returned document_key travels as options.supporting_document_key when creating the payout (POST /v1/payouts); the optional options.document_reference_number is sent to the bank on ach/wire only. A US/USD payout created without the document fails with 400 supporting_document_required; a key uploaded by another account fails with 400 invalid_document_key.
Authorizations
Session JWT (from register/login) or API key (pk_...).
X-API-Key: <token> is accepted as an alternative header.
Query Parameters
Original filename (max 200 chars, no path separators).
Body
The body is of type file.
Response
Document stored; use document_key as options.supporting_document_key of the payout.