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If you don’t see your preferred webhook provider, you can request support for it.
This guide explains how to use ngrok to receive GitLab webhooks on your localhost app. By integrating ngrok with GitLab, you can:
  • Develop and test GitLab webhooks locally without deploying to a public environment or setting up HTTPS.
  • Inspect and troubleshoot requests from GitLab in real time via the inspection UI and API.
  • Modify and replay GitLab webhook requests with a single click instead of reproducing events manually in your GitLab account.
  • Secure your app with GitLab 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:
Then start the app:
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

Once your app is running locally, you’re ready to put it online securely using ngrok.
The ngrok agent uses your authtoken to authenticate when you start a tunnel.
  • Start ngrok:
  • Copy the URL ngrok displays. Your app is now exposed at that URL for use with GitLab.

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3. Configure GitLab to send webhooks

Follow GitLab’s documentation for creating a webhook, and set the following:
  • URL: your ngrok URL (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app).
  • Trigger: choose which events trigger the webhook (for this example, Push events).
  • Secret token: set a token and note it for the verification step below.

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Run webhooks with GitLab and ngrok

After you add the webhook, GitLab sends POST requests to your app when the events you chose occur. The request body varies by event. To trigger a call, push a commit to the repository, or use the webhook’s test option to send a sample push event. Then confirm your localhost app logs the request headers and body in the terminal. You can also review the webhook’s recent events in GitLab to compare what GitLab sent with what your app received.

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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 Traffic Inspector 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 GitLab 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:
  • In your repository, go to Settings and Webhooks, scroll to Project Hooks, and click Edit for your webhook.
  • Enter a value in the Secret token field and click Save changes.
  • Create a Traffic Policy file named gitlab_policy.yml. Replace {your secret token} with the value you entered:
  • Restart ngrok with the policy file:
  • In Project Hooks, click Test and then Push events, or push content to your repository.
Your app should receive the request and log it in the terminal.