Webhooks

Everything that happens asynchronously reaches you as a webhook: a customer replies, a message is delivered or read, a template clears review, a number's quality rating moves. Polling the API for these is the wrong shape — subscribe instead.

The envelope

{
  "id": "evt_01JZQ6F5H7K9M1P3R5T7V9XZBD",
  "object": "event",
  "type": "message.received",
  "created_at": "2026-09-06T09:41:02.114Z",
  "api_version": "2026-09-01",
  "data": { }
}

• id is stable across retries — use it to deduplicate.
• type is the event name. New types are added over time; ignore what you do not handle.
• data holds the resource, in the same shape the REST API returns it.

Responding

Answer 2xx within 5 seconds. Anything else — a timeout, a 4xx, a 5xx — is a failure and the event is retried. Do the work asynchronously: acknowledge first, enqueue second.

app.post("/hooks/sendport", express.raw({ type: "application/json" }), (req, res) => {
  if (!verify(req.body, req.headers["sendport-signature"])) {
    return res.status(400).send("bad signature");
  }

  // Acknowledge immediately, then process off the request path.
  res.sendStatus(200);
  queue.push(JSON.parse(req.body.toString()));
});

Event catalogue