Webhooks

Events

Subscribe by publishing channels.webhooks[] in your shop configuration (an id, a url and the events). The URL must be public https; private, loopback and internal addresses are refused when the configuration is saved and again at send time.

The body

The body is canonical JSON (RFC 8785) and byte-identical on every attempt. data.order is the full signed order.v1 document; data.fromStatus exists only on order.status_changed.

{
  "createdAt": "2026-10-19T09:30:00.000Z",
  "data": {
    "fromStatus": "received",
    "order": {
      "…": "order.v1"
    },
    "orderId": "<order id>",
    "status": "confirmed"
  },
  "id": "<event id>",
  "schemaVersion": 1,
  "tenantId": "<tenant id>",
  "type": "order.status_changed"
}

Headers

Every delivery carries five headers. Deduplicate on CutOptim-Event-Id: a retry and a redelivery repeat it, while CutOptim-Delivery-Id differs.

Verifying the signature

The signature is t=<unix seconds>,v1=<hex HMAC-SHA256(secret, "<t>.<raw body>")>. Accept the delivery when any v1 value matches one of your secrets and t is within 300 seconds of your clock; compare in constant time. Verify the raw bytes before you parse them: a framework that parses and re-serialises the body changes it, and every check fails.

The two receivers below are the reference examples, unchanged: Node 18+ with node:crypto only, and PHP 7.4+ without Composer. Both read the secret from CUTOPTIM_WEBHOOK_SIGNING.

configurator/adapters/reference/node/example-server.mjs

// example-server.mjs - a webhook endpoint on node:http, to read and adapt.   CUTOPTIM_WEBHOOK_SIGNING=whsec_... node example-server.mjs
// (whsec_REPLACE_ME is a placeholder: the real secret comes from the CutOptim admin route.)
import { createServer } from 'node:http';
import { createWebhookReceiver } from './cutoptim-verify.mjs';

const secret = process.env.CUTOPTIM_WEBHOOK_SIGNING;
if (!secret) { console.error('set CUTOPTIM_WEBHOOK_SIGNING (whsec_REPLACE_ME is a placeholder)'); process.exit(1); }

const receive = createWebhookReceiver({
  secrets: [secret],
  async onEvent(event) {
    // event.type === 'order.created'; event.data.order is the signed order document. Store it in YOUR order table here,
    // keyed by event.data.orderId, in the same transaction that records the event id as seen.
    console.log('order.created', event.data.orderId);
  },
});

createServer(async (req, res) => {
  if (req.method !== 'POST') { res.writeHead(405).end(); return; }
  const chunks = []; let size = 0;
  for await (const c of req) { size += c.length; if (size > 2_000_000) { res.writeHead(413).end(); return; } chunks.push(c); }
  const out = await receive({ rawBody: Buffer.concat(chunks), headers: req.headers });   // the RAW bytes, not parsed JSON
  res.writeHead(out.status, { 'Content-Type': 'application/json' }).end(JSON.stringify({ result: out.reason }));
}).listen(Number(process.env.PORT ?? 8787));

configurator/adapters/reference/php/example-webhook.php

<?php
/**
 * example-webhook.php - a webhook endpoint in plain PHP, to read and adapt.
 * CUTOPTIM_WEBHOOK_SIGNING=whsec_... is read from the environment (whsec_REPLACE_ME is a placeholder; the real secret comes from the
 * CutOptim admin route). Replace MemorySeen with a table that has a UNIQUE key on the event id.
 */
require __DIR__ . '/CutOptimVerify.php';

use CutOptim\CutOptimVerify;
use CutOptim\MemorySeen;

$secret = getenv('CUTOPTIM_WEBHOOK_SIGNING');
if ($secret === false || $secret === '') {
    http_response_code(500);
    exit('CUTOPTIM_WEBHOOK_SIGNING is not set');
}

$rawBody = file_get_contents('php://input');   // the RAW bytes, not decoded JSON
$headers = function_exists('getallheaders') ? getallheaders() : [];
$out = CutOptimVerify::handleWebhook($rawBody, $headers, [$secret], new MemorySeen(), static function (array $event): void {
    // $event['type'] === 'order.created'; $event['data']['order'] is the signed order document. Store it in YOUR order table
    // keyed by $event['data']['orderId'], in the same transaction that records the event id as seen.
});

http_response_code($out['status']);
header('Content-Type: application/json');
echo json_encode(['result' => $out['reason']]);

Retries, dead letters and redelivery

A non-2xx answer, a timeout and a redirect are failed attempts. A delivery is tried 6 times in all, with growing waits; after the last failure it is a dead letter. A URL that resolves to a private address is a dead letter at once. Your server can read the delivery log and ask for a redelivery with the secret key (/cfg/v1/admin/deliveries); a redelivery keeps the event id.

Test orders

An order placed with a test key queues no webhook and no e-mail: your ERP and your shoppers never see test traffic.