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This guide shows you how to use ngrok to receive Airship webhook notifications on your localhost app. By integrating ngrok with Airship, you can:
  • Develop and test Airship webhooks locally without deploying to a public environment or setting up HTTPS.
  • Inspect and troubleshoot requests from Airship in real time via the inspection UI and API.
  • Modify and replay Airship webhook requests with a single click instead of reproducing events manually in your Airship account.
  • Secure your app with Airship 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-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

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 Airship.

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3. Configure Airship to send webhooks

Airship can send webhook requests to your app when events occur. To register for those events:
  • Sign in to Airship.
  • On the App Projects page, click one of your projects.
  • Go to Settings, then Open Channels under Channels, and click Configure new Open Channel.
  • Enter My Local Webhook in Display Name, MyLocalWebhook in Name, and paste the ngrok URL in Webhook URL (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app).
  • Click Save.

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Run webhooks with Airship and ngrok

Airship sends different request body contents depending on the event that is triggered. To trigger new calls from Airship to your app:
  • Open your Airship application from the Applications page.
  • Go to Messages, then Messages Overview, and click the + icon in the top right.
  • On the What would you like to create page, click the Message tile.
  • On the Who will receive your message page, select My Local Webhook as the channel and select the users.
  • Go to Content, click Custom Message, and enter any text in Alert Text.
  • Go to Delivery and click Send now.
  • Go to Review & Send and click Send Message.
Confirm your localhost app receives event notifications and logs both headers and body in the terminal.

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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 Airship 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 Airship app, go to Settings, Open Channels under Channels, and click Edit on the My Local Webhook tile.
  • Select Signature in Authentication, enter a value in Secret Key (for example, 12345), and click Update.
  • Create a Traffic Policy file named airship_policy.yml. Replace {your secret} with the value from Secret Key: 
    on_http_request:
  - actions:
      - type: verify-webhook
        config:
          provider: airship
          secret: "{your secret}"
  • Restart ngrok with the policy file: 
    ngrok http 3000 --traffic-policy-file airship_policy.yml
  • Create a new message in Airship to trigger a webhook.
Your app should receive the request and log it in the terminal.