Choose between ACH and wire transfers on the Treasury Prime API and implement each correctly for a given money-movement use case

Steps

1. Retrieve the source account ID via GET /account, then create or retrieve a Counterparty object holding either ACH details (account_number, account_type, routing_number) or wire details, depending on the rail you need.
2. For ACH, POST to /ach with account_id, counterparty_id, amount, direction (credit or debit), and sec_code; track progress via the status attribute (pending → processing → sent, or canceled/error) or the ach.update webhook, since the ACH network itself returns only errors, never synchronous success confirmations.
3. For wires, POST to /wire with the account and counterparty; Treasury Prime queries the sending account for available balance and, if sufficient, sends the wire for settlement — track status via the status attribute (pending, processing, sent, void, error).
4. Weigh the rails' tradeoffs before choosing: ACH is batch-processed and generally cheaper but slower, while wires execute immediately, usually settle within hours, and are more expensive.
5. Account for reversibility and cancellation windows: an ACH transfer can only be canceled while its status is pending (via a PATCH to status=canceled) and can no longer be canceled once it moves to processing; a wire likewise can no longer be canceled once processing begins, and once sent, a wire cannot be reversed at all.
6. Respect each rail's separate processing windows — ACH settles in batches at set daily windows, while wire processing hours vary by partner bank, and a wire submitted outside those hours stays pending until the next window opens.