Sending purchase via orders/paid Webhook and GA4 Measurement Protocol

Why Webhook-driven Purchase

Payment-complete webhook events are generally more reliable for purchase truth than frontend page timing after checkout redirects.

Dummy Send Example

const payload = {
  client_id: "1234567890.1234567890",
  events: [
    {
      name: "purchase",
      params: {
        transaction_id: "ORDER-10001",
        value: 12345,
        currency: "JPY",
      },
    },
  ],
};

await fetch("https://www.google-analytics.com/mp/collect?measurement_id=G-XXXXXXX&api_secret=DUMMY_SECRET", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify(payload),
});

All values above are placeholders for explanation only.

Operational Guardrails

1. Deduplicate by transaction_id
2. Define fallback when client_id is missing
3. Monitor success/failure and prepare retry policy