payment.completed

This is the event most integrations key their fulfilment logic off. It fires once, when a payment first reaches full confirmation for exactly the expected amount — settlement is 100% wallet-to-wallet to your own address; Send Chain never holds the funds.

Payload (data)

{
  "livemode": false,
  "paymentId": "pay_test_00000000",
  "paymentRequestId": "req_test_00000000",
  "origin": { "type": "link", "id": "lnk_test_00000000", "title": "Sample link" },
  "supporter": { "id": "sup_test_00000000", "handle": "sample_supporter", "message": "Test payment" },
  "asset": "USDC",
  "chain": "base",
  "onchainAmount": "15000000",
  "feeAmount": "75000",
  "decimals": 6,
  "fiatValue": { "minor": 1500, "currency": "USD" },
  "rateBasis": "Locked",
  "txRef": "0xtesttx",
  "confirmations": 12,
  "completedAt": "2026-09-13T00:00:00Z"
}

A completed payment can later be undone by a chain reorganisation — see payment.reversed. See Webhooks overview for the envelope, headers, and signature verification shared by every event type.