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.
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.
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.
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.
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.
Store the end-to-end ID and network transaction ID for reconciliation and any future return or inquiry requests.
Known gotchas
RTP and FedNow payments are irrevocable once the receiver's bank accepts them — there is a Request for Return mechanism, but it is voluntary for the receiver; treat these like cash.
The remittance information field (ISO 20022 remittance data for RTP/FedNow) has strict character and format limits; exceeding them or using unsupported characters will cause the payment to be rejected at the network level.
Each sponsor bank wraps the real-time rail in their own proprietary API; there is no single universal endpoint — you must implement against your specific bank's SDK or REST API, and behavior (retry logic, error codes) will differ between providers.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp