Before you go live

Work through this list before you take a real payment. Every item is about your own integration.

• [ ] You have a live key (sk_live_) and you have run one small real payment through it, end to end: invoice, payment, invoice.paid, your order credited. A test key cannot create an invoice today, so this is the only full rehearsal there is.
• [ ] Your webhook handler is idempotent on event.id. A retry, a slow response and an operator replay all arrive as the same event id.
• [ ] You verify against the RAW request body, and you answer 400 on a signature refusal, never 5xx. How.
• [ ] You credit on invoice.paid, not on invoice.payment_detected. A detected payment is not settled and the chain can still take it back.
• [ ] You handle invoice.settled_payment_reorged. The invoice stays paid; this event is the only thing that tells you the money is gone. Paging a human is a legitimate handler.
• [ ] Your Idempotency-Keys are derived from your own order ids, not generated per call, so a timeout at your process boundary is recoverable. Why.
• [ ] You parse token amounts with BigInt. token_base_units, received_base_units, amount_base_units and network_fee.native_base_units are decimal strings because they do not fit a JavaScript number.
• [ ] You branch on livemode. Test and live events arrive at the same URL.
• [ ] You have handled a failure, not just the happy path. With a live key and small amounts: an invoice you never pay (it becomes expired), and a payment smaller than the invoice (it becomes underpaid and stays open). Your code should also accept invoice.paid_late, which you can read about in the quickstart.

Next

• Webhooks: the signature check and the retry ladder.
• Errors: what each code means.