Building a Basic Webhook Receiver with Node.js and Express

const express = require('express');
const bodyParser = require('body-parser');

const app = express();
const PORT = process.env.PORT || 3000;

// Use body-parser middleware to parse JSON request bodies
// Some webhook providers might send different content types, e.g., 'text/plain'
// For JSON webhooks:
app.use(bodyParser.json());

// For raw body access (e.g., for signature verification, uncomment below and remove above line)
// app.use(bodyParser.raw({ type: 'application/json' })); 

app.post('/webhook', (req, res) => {
  console.log('--- Webhook Received ---');
  // The payload will be in req.body if using bodyParser.json()
  // If using bodyParser.raw(), req.body would be a Buffer.
  console.log('Payload:', req.body);

  // For production, you'd typically:
  // 1. Verify webhook signature (if provided by the service).
  // 2. Validate the payload structure.
  // 3. Process the event (e.g., update database, trigger other services).
  // 4. Respond quickly to avoid webhook provider timeouts.

  // Example of processing based on an 'event_type'
  if (req.body && req.body.event_type === 'user.created') {
    console.log(`New user created: ${req.body.user_id}`);
    // ... perform specific action ...
  } else if (req.body && req.body.event_type === 'order.updated') {
    console.log(`Order updated: ${req.body.order_id}`);
    // ... perform specific action ...
  }

  // Acknowledge receipt to the webhook sender
  res.status(200).send('Webhook received successfully!');
});

// Basic health check endpoint
app.get('/', (req, res) => {
  res.status(200).send('Webhook receiver is running.');
});

app.listen(PORT, () => {
  console.log(`Webhook receiver listening on port ${PORT}`);
});