Upload an INVOICE or RECEIPT (PDF, image, or .zip of them) for analysis. file_base64 is the file's raw bytes, base64-encoded. direction is payable (incoming supplier invoice) or receivable (outgoing). Creates Item(s) and queues extraction.

This door is invoices-only: it never routes a file onward by type, so a bank statement, a journal export or a balance sheet sent here is analysed and then just sits as a document. For anything that is not an invoice — or when you are not sure what the file is — use upload_intake.