Integrations

PayPal Webhooks Guide

PayPal webhooks carry payment and checkout events that often update orders, fulfillment, subscriptions, account state, and customer notifications. Because those events touch money and customer access, delivery needs signature verification, idempotency, and a recovery path for failed destinations.

FastHook gives PayPal a stable source URL, verifies PayPal transmission signatures against the configured webhook id, stores request evidence, and lets teams retry or replay failed payment event deliveries safely.

Provider webhook recovery map for payment event routing.
Keep PayPal payment recovery scoped. Retry one destination event before replaying a billing or fulfillment window.

PayPal signature headers

  • paypal-transmission-id: transmission id included in the signed payload.
  • paypal-transmission-time: transmission time included in the signed payload.
  • paypal-transmission-sig: Base64 RSA signature.
  • paypal-cert-url: PayPal certificate URL used for public key lookup.
  • paypal-auth-algo: expected signature algorithm.

Create a PayPal source

Create PayPal source
curl -X POST "https://api.fasthook.io/v1/sources" \
  -H "Authorization: Bearer $FASTHOOK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "PayPal production",
    "type": "PAYPAL",
    "config": {
      "auth_type": "PROVIDER_SIGNATURE",
      "auth": {
        "provider": "PAYPAL",
        "webhook_id": "WH-..."
      },
      "allowed_http_methods": ["POST", "PUT", "PATCH", "DELETE"]
    }
  }'

Production checklist

  • Use separate FastHook sources for PayPal sandbox and production.
  • Use idempotency before changing order, invoice, or entitlement state.
  • Route payment, dispute, and checkout event families to separate destinations.
  • Inspect failed attempts before replaying a payment event window.
  • Throttle replay into fulfillment and billing systems.

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