GitHub Webhooks Skill

When to Use This Skill

• Setting up GitHub webhook handlers
• Debugging signature verification failures
• Understanding GitHub event types and payloads
• Handling push, pull request, or issue events

Verification (core)

GitHub signs the raw body with HMAC-SHA256 keyed on your webhook secret and sends the digest in X-Hub-Signature-256 formatted as sha256=<hex>. Use X-Hub-Signature-256 (not the legacy SHA-1 X-Hub-Signature), pass the raw body, and compare timing-safe.

Node:

const crypto = require('crypto');

function verify(rawBody, signatureHeader, secret) {
  const [algo, sig] = (signatureHeader || '').split('=');
  if (algo !== 'sha256' || !sig) return false;
  const expected = crypto.createHmac('sha256', secret).update(rawBody).digest('hex');
  try {
    return crypto.timingSafeEqual(Buffer.from(sig), Buffer.from(expected));
  } catch {
    return false;
  }
}

Python:

import hmac, hashlib

def verify(raw_body: bytes, signature_header: str, secret: str) -> bool:
    algo, _, sig = (signature_header or "").partition("=")
    if algo != "sha256" or not sig:
        return False
    expected = hmac.new(secret.encode(), raw_body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(sig, expected)

For complete handlers with route wiring, event dispatch, and tests, see:

• examples/express/
• examples/nextjs/
• examples/fastapi/

Common Event Types

For full event reference, see GitHub Webhook Events

Important Headers

Environment Variables

GITHUB_WEBHOOK_SECRET=your_webhook_secret   # Set when creating webhook in GitHub

Local Development

# Start tunnel (no account needed)
npx hookdeck-cli listen 3000 github --path /webhooks/github

Reference Materials

• references/overview.md - GitHub webhook concepts
• references/setup.md - Configuration guide
• references/verification.md - Signature verification details