@better-webhook/express

Wire Express to Better Webhook while preserving the raw body bytes and raw headers required for provider signature verification.

@better-webhook/express is the framework adapter for Express applications. It turns an Express request with a captured req.rawBody into the Raw Delivery Request contract expected by @better-webhook/core, then sends the core Webhook Response through Express.

Why use this package?

• Keep provider verification inside the Better Webhook pipeline.
• Preserve raw request bytes before body parsers mutate req.body.
• Use req.rawHeaders when available so duplicate header lines are represented.
• Send consistent provider responses from core's response policy.
• Keep Express request and response objects out of event handlers.

Installation

Install the Express adapter with core and a provider package:

pnpm add @better-webhook/core @better-webhook/express @better-webhook/stripe

Getting started

Capture the raw body before parsed body middleware touches the webhook route, then delegate to the Better Webhook middleware:

import express from "express";
import { createWebhookEndpoint } from "@better-webhook/core";
import { createExpressMiddleware } from "@better-webhook/express";
import { stripe } from "@better-webhook/stripe";

const app = express();

const endpoint = createWebhookEndpoint({
  provider: stripe({ signingSecret: process.env.STRIPE_WEBHOOK_SECRET! }),
  handlers: {
    "invoice.paid": async ({ event }) => {
      event.payload.status;
    },
  },
});

app.post(
  "/webhooks/stripe",
  express.raw({ type: "application/json" }),
  (req, _res, next) => {
    req.rawBody = req.body;
    next();
  },
  createExpressMiddleware(endpoint),
);

If your application uses express.json() globally, register the webhook route before that parser or exclude the webhook route from parsed body middleware.

How it fits with Better Webhook

@better-webhook/express is a Framework Adapter. It does not implement provider verification, replay protection, idempotency, event parsing, or handler dispatch. Those stay in @better-webhook/core and the selected provider package.

This package only adapts:

• Express requests with captured raw bodies to core Raw Delivery Requests.
• Core Webhook Responses to Express responses.

Behavior and safety notes

The adapter requires req.rawBody. If req.rawBody is missing, conversion to a Raw Delivery Request throws because provider signatures cannot be verified against a parsed or reserialized body.

When req.rawHeaders is available, the adapter uses it to preserve duplicate raw header lines. If req.rawHeaders is not present, it falls back to req.headers.

Event handlers receive Better Webhook's framework-neutral Handler Context. They do not receive Express req, res, or next.

API summary

• createExpressMiddleware(endpoint): creates Express middleware for a Better Webhook endpoint.
• toRawDeliveryRequest(request): converts an Express-shaped request into a core Raw Delivery Request.
• sendExpressResponse(response, webhookResponse): sends a core Webhook Response through Express.
• expressRawHeaderCapabilities: describes raw body and raw header preservation.
• ExpressWebhookRequest, ExpressWebhookResponse, ExpressNextFunction: minimal framework types used by the adapter.

Runtime support and limits

• Node.js 18 or newer.
• ESM-only package with TypeScript declarations.
• The webhook route must preserve raw body bytes before parsed body middleware.