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

​
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 Calendly.

​
3. Configure Calendly to send webhooks

Calendly registers webhooks through its API rather than a dashboard form. Follow Calendly’s guide for creating a webhook subscription, which covers creating a personal access token and sending the registration request with your organization and user URIs. Set the following in your request:
  • url: your ngrok URL (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app).
  • events: choose which events trigger the webhook (for this example, invitee.created and invitee.canceled).
  • scope: the level the webhook applies to (for this example, user).
Your registration request looks like this:
Replace URL with your ngrok URL, TOKEN with your personal access token, ORGANIZATION_URL and USER_URL with your organization and user URIs, and KEY with your signing key.

​
Run webhooks with Calendly and ngrok

Calendly sends a different request body for each event type. Book a meeting through your Calendly scheduling link to trigger a new event. Confirm your app receives the invitee.created event and logs its headers and body in the terminal.

​
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

​
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 Calendly 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 Calendly, go to Integrations, API and webhooks, and copy the API Key value (the same value you used to register your webhook).
  • Create a Traffic Policy file named calendly_policy.yml. Replace {your key} with the value you copied:
  • Restart ngrok with the policy file:
  • Schedule a meeting from your Calendly link to trigger the webhook.
Your app should receive the request and log it in the terminal.