Webhooks | Northwind

Webhooks tell your systems when something happens in Northwind, so you don’t have to keep asking the API.

Add an endpoint

In Settings → API and webhooks, click Add endpoint, enter your URL and pick the events.

Events

Event	Sent when
`invoice.sent`	An invoice is emailed
`invoice.paid`	It’s paid in full
`invoice.overdue`	The due date passes unpaid
`payment.refunded`	A payment is refunded

Verify signatures

Each request is signed. Check the Northwind-Signature header with your endpoint’s secret before you trust it, comparing in constant time:

JavaScript

import crypto from "node:crypto";

const expected = crypto.createHmac("sha256", secret).update(rawBody).digest();
const received = Buffer.from(req.headers["northwind-signature"] ?? "", "hex");
if (received.length !== expected.length || !crypto.timingSafeEqual(received, expected)) {
  return res.status(400).end();
}