send a real-time payment (RTP or FedNow) through a sponsor-bank API

Steps

1. Confirm your sponsor bank supports the target rail (RTP via The Clearing House, or FedNow via the Federal Reserve) and that the receiving bank is a participant on that rail.
2. Verify the receiving account using the bank's account validation endpoint or a small ACH prenote if the sponsor bank API supports it; RTP/FedNow are irrevocable, making pre-validation important.
3. Construct the payment request per your sponsor bank's API schema — fields typically include sender account, receiver routing number, receiver account number, amount (in cents), remittance information (up to 140 characters for RTP), and a unique end-to-end ID.
4. POST the payment request to your sponsor bank's RTP or FedNow initiation endpoint; a synchronous or near-synchronous response will indicate whether the payment was accepted into the network.
5. Handle the response: a successful submission returns a network transaction ID; monitor for final status (COMPLETED or RJCT — rejected) via webhook or status polling, as the network response can take a few seconds.
6. Store the end-to-end ID and network transaction ID for reconciliation and any future return or inquiry requests.