Real-time versus batch rails, authorisation through settlement, payment initiation, returns and reversals.
3 questions in Banking & Financial Services.
Everything you did in the overnight window has to happen inside a few seconds, the payment becomes irrevocable so recall is a request rather than a right, an unanswered request leaves an unknown state you must resolve by enquiry, and liquidity plus availability become continuous obligations.
Prevent a double charge on payment retry with an idempotency key tied to the purchase intent, a unique constraint, atomic charge recording, honest in-flight retry responses and settlement reconciliation.
You cannot substitute the rail, so the work is triage, finality and communication - deciding which payments genuinely must settle today, whether any alternative gives the receiver the same certainty, and what you tell the customer before the window closes. The backlog on recovery is the second incident.