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

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3. Configure Pinwheel to send webhooks

Pinwheel can send webhook requests to your app when events occur in your account. To register for those events:
  • Sign in to the Pinwheel Developer Portal.
  • On the Dashboard, open the API Keys tab, click Reveal Secret, and note the API Secret and Server values.
  • Create the webhook with curl (replace SERVER_URL, NGROK_URL, and API_SECRET with your values): 
    curl --request POST --url SERVER_URL/v1/webhooks \
--header 'x-api-secret: API_SECRET' \
--header 'Content-Type: application/json' --data '{
    "url": "NGROK_URL",
    "status": "active",
    "enabled_events": [
        "account.added",
        "employment.added",
        "identity.added",
        "income.added"
    ]
}'
  • Confirm the response JSON has a status attribute with value active.

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Run webhooks with Pinwheel and ngrok

Pinwheel sends different request body contents depending on the events you enabled. With account.added subscribed, you can trigger calls by having users log into their payroll accounts via the Pinwheel API. Confirm your localhost app receives the event 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 Pinwheel 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 pinwheel_policy.yml. Replace {your api secret} with the API Secret you noted when creating the webhook: 
    on_http_request:
  - actions:
      - type: verify-webhook
        config:
          provider: pinwheel
          secret: "{your api secret}"
  • Restart ngrok with the policy file: 
    ngrok http 3000 --traffic-policy-file pinwheel_policy.yml
  • Trigger an event (for example, via the Pinwheel API) to send a request.
Your app should receive the request and log it in the terminal.