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Sentry Webhooks

This guide covers how to use ngrok to integrate your localhost app with Sentry by using Webhooks. Sentry webhooks can be used to notify an external application whenever specific events occur in your Sentry projects.

By integrating ngrok with Sentry, you can:

  • Develop and test Sentry webhooks locally, eliminating the time in deploying your development code to a public environment and setting it up in HTTPS.
  • Inspect and troubleshoot requests from Sentry in real-time via the inspection UI and API.
  • Modify and Replay Sentry Webhook requests with a single click and without spending time reproducing events manually in your Sentry account.
  • Secure your app with Sentry validation provided by ngrok. Invalid requests are blocked by ngrok before reaching your app.

Step 1: Start your app

For this tutorial, we'll use the sample NodeJS app available on GitHub.

To install this sample, run the following commands in a terminal:

git clone
cd ngrok-webhook-nodejs-sample
npm install

This will get the project installed locally.

Now you can launch the app by running the following command:

npm start

The app runs by default on port 3000.

You can validate that the app is up and running by visiting http://localhost:3000. The application logs request headers and body in the terminal and responds with a message in the browser.

Step 2: Launch ngrok

Once your app is running successfully on localhost, let's get it on the internet securely using ngrok!

  1. If you're not an ngrok user yet, just sign up for ngrok for free.

  2. Download the ngrok agent.

  3. Go to the ngrok dashboard and copy your Authtoken.
    Tip: The ngrok agent uses the auth token to log into your account when you start a tunnel.

  4. Start ngrok by running the following command:

    ngrok http 3000
  5. ngrok will display a URL where your localhost application is exposed to the internet (copy this URL for use with Sentry). ngrok agent running

Step 3: Integrate Sentry

To register a webhook on your Sentry account follow the instructions below:

  1. Access Sentry and sign in using your Sentry account.

  2. On your Sentry organization page, click Settings on the left menu, click Developer Settings on the Organization sub-menu, and then click Create new integration.

  3. On the Choose Integration Type popup, choose Internal Integration and then click Next.

  4. On the Create Internal Integration page, enter My Local App Webhook in the Name field and then enter the URL provided by the ngrok agent to expose your application to the internet in the Webhook URL field (i.e. URL to Publish

  5. Under the PERMISSIONS section, select Read & Write for the Issue & Event field, click the issue checkbox under the WEBHOOKS section, and then click Save Changes.

Run Webhooks with Sentry and ngrok

Sentry sends different request body contents depending on the event that is being triggered. You can trigger new calls from Sentry to your application by following the instructions below.

  1. On your Sentry organization page, click Issues on the left menu.

  2. On the Issues page, open an issue by clicking its name.

    Note: If you don't have any issues click Create a sample event.

  3. Click Resolve.

    Confirm your localhost app receives a notification and logs both headers and body in the terminal.

Optionally, you can verify the log of the webhook call in Sentry:

  1. On the left menu, click Settings, click Developer Settings, and then click Dashboard for My Local App Webhook. Webhook Logs

Inspecting requests

When you launch the ngrok agent on your local machine, you can see two links:

  • The URL to your app (it ends with for free accounts or for paid accounts when not using custom domains)
  • A local URL for the Web Interface (a.k.a Request Inspector).

The Request Inspector shows all the requests made through your ngrok tunnel to your localhost app. When you click on a request, you can see details of both the request and the response.

Seeing requests is an excellent way of validating the data sent to and retrieved by your app via the ngrok tunnel. That alone can save you some time dissecting and logging HTTP request and response headers, methods, bodies, and response codes within your app just to confirm you are getting what you expect.

To inspect Sentry's webhooks call, launch the ngrok web interface (i.e., and then click one of the requests sent by Sentry.

From the results, review the response body, header, and other details:

ngrok Request Inspector

Replaying requests

The ngrok Request Inspector provides a replay function that you can use to test your code without the need to trigger new events from Sentry. To replay a request:

  1. In the ngrok inspection interface (i.e. http://localhost:4040), select a request from Sentry.

  2. Click Replay to execute the same request to your application or select Replay with modifications to modify the content of the original request before sending the request.

  3. If you choose to Replay with modifications, you can modify any content from the original request. For example, you can modify the id field inside the body of the request.

  4. Click Replay.

Verify that your local application receives the request and logs the corresponding information to the terminal.

Secure webhook requests

The ngrok signature webhook verification feature allows ngrok to assert that requests from your Sentry webhook are the only traffic allowed to make calls to your localhost app.

Note: This ngrok feature is limited to 500 validations per month on free ngrok accounts. For unlimited, upgrade to Pro or Enterprise.

This is a quick step to add extra protection to your application.

  1. Access Sentry and sign in using your Sentry account.

  2. On your Sentry organization page, click Settings on the left menu, click Developer Settings on the Organization sub-menu, click My Local App Webhook, and then copy the value of the Client Secret field under the CREDENTIALS section.

  3. Restart your ngrok agent by running the command, replacing {your client secret} with the value you have copied before (See Integrate ngrok and Sentry.):

    ngrok http 3000 --verify-webhook sentry --verify-webhook-secret {your client secret}
  4. Repeat the steps in the Run Webhooks with Sentry and ngrok section to create and resolve an issue.

Verify that your local application receives the request and logs information to the terminal.