Vercel Webhooks

Vercel Webhooks

When to Use This Skill

• Setting up Vercel webhook handlers
• Debugging signature verification failures
• Understanding Vercel event types and payloads
• Handling deployment, project, domain, or integration events
• Monitoring deployment status changes

Essential Code (USE THIS)

Express Webhook Handler with Manual Verification

const express = require('express');
const crypto = require('crypto');

const app = express();

// CRITICAL: Use express.raw() for webhook endpoint - Vercel needs raw body
app.post('/webhooks/vercel',
  express.raw({ type: 'application/json' }),
  async (req, res) => {
    const signature = req.headers['x-vercel-signature'];

    if (!signature) {
      return res.status(400).send('Missing x-vercel-signature header');
    }

    // Verify signature using SHA1 HMAC
    const expectedSignature = crypto
      .createHmac('sha1', process.env.VERCEL_WEBHOOK_SECRET)
      .update(req.body)
      .digest('hex');

    // Use timing-safe comparison
    let signaturesMatch;
    try {
      signaturesMatch = crypto.timingSafeEqual(
        Buffer.from(signature),
        Buffer.from(expectedSignature)
      );
    } catch (err) {
      // Buffer length mismatch = invalid signature
      signaturesMatch = false;
    }

    if (!signaturesMatch) {
      console.error('Invalid Vercel webhook signature');
      return res.status(400).send('Invalid signature');
    }

    // Parse the verified payload
    const event = JSON.parse(req.body.toString());

    // Handle the event
    switch (event.type) {
      case 'deployment.created':
        console.log('Deployment created:', event.payload.deployment.id);
        break;
      case 'deployment.succeeded':
        console.log('Deployment succeeded:', event.payload.deployment.id);
        break;
      case 'deployment.error':
        console.log('Deployment failed:', event.payload.deployment.id);
        break;
      case 'project.created':
        console.log('Project created:', event.payload.project.name);
        break;
      default:
        console.log('Unhandled event:', event.type);
    }

    res.json({ received: true });
  }
);

Python (FastAPI) Webhook Handler

import os
import hmac
import hashlib
from fastapi import FastAPI, Request, HTTPException, Header

app = FastAPI()
webhook_secret = os.environ.get("VERCEL_WEBHOOK_SECRET")

@app.post("/webhooks/vercel")
async def vercel_webhook(
    request: Request,
    x_vercel_signature: str = Header(None)
):
    if not x_vercel_signature:
        raise HTTPException(status_code=400, detail="Missing x-vercel-signature header")

    # Get raw body
    body = await request.body()

    # Compute expected signature
    expected_signature = hmac.new(
        webhook_secret.encode(),
        body,
        hashlib.sha1
    ).hexdigest()

    # Timing-safe comparison
    if not hmac.compare_digest(x_vercel_signature, expected_signature):
        raise HTTPException(status_code=400, detail="Invalid signature")

    # Parse verified payload
    event = await request.json()

    # Handle event
    if event["type"] == "deployment.created":
        print(f"Deployment created: {event['payload']['deployment']['id']}")
    elif event["type"] == "deployment.succeeded":
        print(f"Deployment succeeded: {event['payload']['deployment']['id']}")
    # ... handle other events

    return {"received": True}

For complete working examples with tests, see:

• examples/express/ - Full Express implementation
• examples/nextjs/ - Next.js App Router implementation
• examples/fastapi/ - Python FastAPI implementation

Common Event Types

See references/overview.md for the complete event list.

Environment Variables

# Required
VERCEL_WEBHOOK_SECRET=your_webhook_secret_from_dashboard

# Optional (for API calls)
VERCEL_TOKEN=your_vercel_api_token

Local Development

For local webhook testing, install Hookdeck CLI:

# Install via npm
npm install -g hookdeck-cli

# Or via Homebrew
brew install hookdeck/hookdeck/hookdeck

Then start the tunnel:

hookdeck listen 3000 --path /webhooks/vercel

No account required. Provides local tunnel + web UI for inspecting requests.

Reference Materials

• Webhook Overview - What Vercel webhooks are, all event types
• Setup Guide - Configure webhooks in Vercel dashboard
• Signature Verification - SHA1 HMAC verification details

Recommended: webhook-handler-patterns

For production-ready webhook handling, also install the webhook-handler-patterns skill to learn:

• Handler sequence - Correct order of operations
• Idempotency - Handle duplicate webhooks
• Error handling - Proper status codes and retries
• Retry logic - Handle transient failures

Related Skills

• stripe-webhooks - Stripe payment webhooks
• github-webhooks - GitHub repository webhooks
• shopify-webhooks - Shopify store webhooks
• sendgrid-webhooks - SendGrid email webhooks
• webhook-handler-patterns - Idempotency, error handling, retry logic
• hookdeck-event-gateway - Webhook infrastructure that replaces your queue — guaranteed delivery, automatic retries, replay, rate limiting, and observability for your webhook handlers