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This guide walks you through using ngrok to receive GitHub repository webhooks on your localhost app. By integrating ngrok with GitHub, you can:
  • Develop and test GitHub webhooks locally without deploying to a public environment or setting up HTTPS.
  • Inspect and troubleshoot requests from GitHub in real time via the inspection UI and API.
  • Modify and replay GitHub webhook requests with a single click instead of reproducing events manually in GitHub.
  • Secure your app with GitHub webhook validation provided by ngrok. Invalid requests are blocked by ngrok before reaching your app.

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What you’ll need

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1. Start your app

For this tutorial, you can use the sample Node.js app on GitHub. To install the sample, run the following in a terminal: 
git clone https://github.com/ngrok/ngrok-webhook-nodejs-sample.git
cd ngrok/ngrok-webhook-nodejs-sample
npm install
Then start the app: 
npm start
The app runs on port 3000 by default. You can confirm it’s running by visiting http://localhost:3000. The app logs request headers and body in the terminal and shows a message in the browser.

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2. Expose your app with ngrok

With your app running locally, expose it with ngrok.
The ngrok agent uses your authtoken to authenticate when you start a tunnel.
  • Start ngrok: 
    ngrok http 3000
  • Copy the URL ngrok displays. Your app is now exposed at that URL for use with GitHub.

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3. Configure GitHub to send webhooks

GitHub can send webhook requests to your app when repository events occur. To register for those events:
  • Sign in to GitHub.
  • Open a repository from your repositories list.
If you don’t have a repository, create an empty one first.
  • In the repository, go to Settings and select Webhooks in the left menu.
  • Click Add webhook.
  • In Payload URL, paste the ngrok URL (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app).
  • Set Content type to application/json.
  • Choose which events trigger the webhook (for this example, select Just the push event).
  • Leave the webhook active and click Add webhook.

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Run webhooks with GitHub and ngrok

After you add the webhook, GitHub sends POST requests to your app through ngrok. To compare what GitHub sends with what your app receives:
  • Open the webhook you created.
  • Click the Recent Deliveries tab.
  • Select a delivery by ID.
Compare that delivery’s headers and body with what your application received; they should match.
The payload your app receives depends on the events you chose. Because this example uses Just the push event, push changes to the repository to trigger new webhook calls. To resend a request, click Redeliver in the Recent Deliveries tab on the webhook page.

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Inspecting requests

ngrok’s Traffic Inspector captures all requests made through your ngrok endpoint to your localhost app. Select any request to view detailed information about both the request and response.
To avoid exposing secrets, accounts only collect traffic metadata by default. You must enable full capture in the Observability section of your account settings to capture complete request and response data.
Use the traffic inspector to:
  • Validate webhook payloads and response data
  • Debug request headers, methods, and status codes
  • Troubleshoot integration issues without adding logging to your app

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Replaying requests

Test your webhook handling code without triggering new events from your service using the Traffic Inspector’s replay feature:
  1. Send a test webhook from your service to generate traffic in your Traffic Inspector.
  2. Select the request you want to replay in the traffic inspector.
  3. Choose your replay option:
    • Click Replay to send the exact same request again
    • Select Replay with modifications to edit the request before sending
  4. (Optional) Modify the request: Edit any part of the original request, such as changing field values in the request body.
  5. Send the request by clicking Replay.
Your local application will receive the replayed request and log the data to the terminal.

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Secure webhook requests

ngrok can verify that incoming requests are from your GitHub webhook so only that traffic reaches your app.
Webhook verification is limited to 500 validations per month on free accounts. If you need more, you can upgrade to Hobbyist or Pay-as-you-go. See TPU Pricing for details.
To add verification:
  • Create a Traffic Policy file named github_policy.yml. Replace {your secret} with the Secret from your GitHub webhook: 
    on_http_request:
  - actions:
      - type: verify-webhook
        config:
          provider: github
          secret: "{your secret}"
  • Restart ngrok with the policy file: 
    ngrok http 3000 --traffic-policy-file github_policy.yml
  • Resend a delivery from your GitHub webhook.
Your app should receive the request and log it in the terminal.