Skip to main content
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.

​
What you’ll need

​
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-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.

​
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: 
    ngrok http 3000
  • Copy the URL ngrok displays. Your app is now exposed at that URL for use with GitLab.

​
3. Configure GitLab to send webhooks

GitLab can send webhook requests to your app when events occur in a repository. To register for those events:
  • Sign in to GitLab.
  • Select a repository from the Your Repository list.
If you don’t have a repository, create a new empty one.
  • In the repository, click Settings and then Webhooks.
  • On the Webhooks page, enter your ngrok URL in the URL field (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app).
  • Check Push events under Trigger and click Add webhook.
  • Scroll to the Project Hooks section, click Test for your webhook, and then click Push events.
Confirm your localhost app receives the test event and logs both headers and body in the terminal. You can verify the request in GitLab: click Edit for your webhook, scroll to Recent events, and click View details for the Push Hook line.

​
Run webhooks with GitLab and ngrok

With Push events as the trigger, GitLab sends a post request to your app when you push to the repository. To trigger a call:
  • Click your repository name at the top of the left menu.
  • On the project page, click + and then New file.
  • On the New file page, enter a File name and add content (for example, This is my file content).
  • Click Commit changes.
Confirm your localhost app receives the push event and logs both headers and body in the terminal. Alternatively, clone the repository locally, add and commit changes, then push: git add .; git commit -m "my first commit"; git push

​
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

​
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.

​
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: 
    on_http_request:
  - actions:
      - type: verify-webhook
        config:
          provider: gitlab
          secret: "{your secret token}"
  • Restart ngrok with the policy file: 
    ngrok http 3000 --traffic-policy-file gitlab_policy.yml
  • 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.