Responding

Answer quickly, work later

Paydot allows 3 seconds to connect and 5 seconds for the response. Anything slower counts as a failure and is retried. A slow handler produces duplicate deliveries instead of a late success.

Return a 2xx as soon as the event is safely queued, not once your downstream work has finished.

// Good: acknowledge first, process out of band.
enqueue(event);
res.sendStatus(202);

Deduplicate on the event id

Delivery is at least once. A retry reuses the same Paydot-Event-Id, so recording processed ids is enough to make your handler idempotent.

INSERT INTO processed_webhooks (event_id) VALUES ($1)
ON CONFLICT (event_id) DO NOTHING;

A single payment can legitimately produce several different events (EXECUTED then SETTLED), so deduplicating on the payment id instead would silently drop a real status change.

Ordering is not guaranteed

Events can arrive out of order. Use data.payment.updatedAt, not arrival order, when deciding which of two events is newer.