# GitHub Webhooks

## 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:

```javascript
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:

```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/](https://github.com/hookdeck/webhook-skills/tree/main/skills/github-webhooks/examples/express/)
> * [examples/nextjs/](https://github.com/hookdeck/webhook-skills/tree/main/skills/github-webhooks/examples/nextjs/)
> * [examples/fastapi/](https://github.com/hookdeck/webhook-skills/tree/main/skills/github-webhooks/examples/fastapi/)

## Common Event Types

| Event | Description |
| --- | --- |
| `push` | Commits pushed to branch |
| `pull_request` | PR opened, closed, merged, etc. |
| `issues` | Issue opened, closed, labeled, etc. |
| `release` | Release published |
| `workflow_run` | GitHub Actions workflow completed |
| `ping` | Test event when webhook created |

> For full event reference, see [GitHub Webhook Events](https://docs.github.com/en/webhooks/webhook-events-and-payloads)

## Important Headers

| Header | Description |
| --- | --- |
| `X-Hub-Signature-256` | HMAC SHA-256 signature (use this, not sha1) |
| `X-GitHub-Event` | Event type (push, pull_request, etc.) |
| `X-GitHub-Delivery` | Unique delivery ID |

## Environment Variables

```bash
GITHUB_WEBHOOK_SECRET=your_webhook_secret   # Set when creating webhook in GitHub

```

## Local Development

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

```

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/github-webhooks/references/overview.md) - GitHub webhook concepts
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/github-webhooks/references/setup.md) - Configuration guide
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/github-webhooks/references/verification.md) - Signature verification details