Idempotency You Can See
Duplicate events and accidental replays are common in webhook-driven tools. Create visible idempotency through unique keys, checksum fields, and ledger-like tables that record processed inputs. Reference stable identifiers such as order numbers, email hashes, or external IDs. Before taking actions, check the registry, short-circuit duplicates, and annotate outcomes. The result is a workflow that tolerates retries without double-charging, double-emailing, or double-creating records, turning a chaotic edge case into a calm, consistent behavior.