GitHub Guias de prueba de webhooks

Replay + helper de firma (dashboard)

Open /dashboard or /dashboard/tunnels and use Webhook Command Center for this provider. It gives one-click replay and signature verification helpers.

instatunnel webhook verify --provider github --secret-env GITHUB_WEBHOOK_SECRET

curl -i -X POST "https://YOUR-SUBDOMAIN.instatunnel.my/webhooks/github" -H "Content-Type: application/json" --data-binary @sample-github.json

Required signature header: x-hub-signature-256

1. Setup local de app

Create a local webhook endpoint at: /webhooks/github

import express from 'express'
import crypto from 'crypto'

const app = express()
app.post('/webhooks/github', express.raw({ type: 'application/json' }), (req, res) => {
  const signature = req.header('x-hub-signature-256') || ''
  const rawBody = req.body as Buffer
  const expected = 'sha256=' + crypto
    .createHmac('sha256', process.env.GITHUB_WEBHOOK_SECRET!)
    .update(rawBody)
    .digest('hex')

  const signatureBuf = Buffer.from(signature)
  const expectedBuf = Buffer.from(expected)
  const valid =
    signatureBuf.length === expectedBuf.length &&
    crypto.timingSafeEqual(signatureBuf, expectedBuf)

  if (!valid) {
    return res.status(401).send('invalid signature')
  }

  console.log('github event:', req.header('x-github-event'))
  res.status(200).send('ok')
})

app.listen(3000, () => console.log('listening on :3000'))

2. Ejecutar comando InstaTunnel

instatunnel 3000 --subdomain github-hooks

Keep a fixed subdomain so your provider dashboard URL does not keep changing.

3. Campos a pegar en proveedor

Use the helper below to generate exact values with your chosen subdomain and path.

4. Enviar evento de prueba

1. In repository settings, open the webhook and click "Redeliver" on a recent delivery.
2. Or click "Test delivery" after saving webhook settings.
3. Check your app logs for event type and successful signature check.

5. Verificar firma

Verify this header on every request: x-hub-signature-256

const expected = 'sha256=' + crypto
  .createHmac('sha256', process.env.GITHUB_WEBHOOK_SECRET!)
  .update(rawPayloadBuffer)
  .digest('hex')

const valid = Buffer.from(signature).length === Buffer.from(expected).length &&
  crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected))
if (!valid) return res.status(401).send('invalid signature')

6. Reintentos e idempotencia

• Use GitHub delivery ID as your idempotency key.
• Persist processed delivery IDs for a safe replay window.
• Handle out-of-order events by reading current resource state before mutating.

7. Fallos comunes y solucion rapida