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

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3. Configure Contentful to send webhooks

Contentful can send webhook requests to your app when events occur in your account. To register for those events:
  • Sign in to the Contentful site.
  • On the home page, click Settings in the top menu, click Webhooks, and then click Add Webhook.
  • On the Webhook page, enter a name in Name, enter your ngrok URL in the URL field (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app).
  • Ensure the Active switch is on and Trigger for all events is selected under Triggers.
  • Select application/json for Content type and click Save.

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Run webhooks with Contentful and ngrok

Contentful sends different request body contents depending on the event. To trigger new calls from Contentful to your app:
  • On the Contentful site, click Media in the top menu, click Add Asset, and then click Single asset.
  • On the Asset page, drag and drop an image into the File area and click Publish.
Confirm your localhost app receives two event notifications and logs both headers and body in the terminal. You can verify the webhook in Contentful: go to Settings, Webhooks, click your webhook, and open the Activity log tab.

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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 Contentful 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:
  • When you created the webhook in Contentful, you set a signing secret; copy that value (or create a new webhook and note the signing secret).
  • Create a Traffic Policy file named contentful_policy.yml. Replace {your webhook signing secret} with the value from Contentful: 
    on_http_request:
  - actions:
      - type: verify-webhook
        config:
          provider: contentful
          secret: "{your webhook signing secret}"
  • Restart ngrok with the policy file: 
    ngrok http 3000 --traffic-policy-file contentful_policy.yml
  • Publish an asset or make another change that triggers your webhook.
Your app should receive the request and log it in the terminal.