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

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3. Configure Box to send webhooks

Box can send webhook requests to your app when events occur in your account. To register for those events:
  • Sign in to Box and click Dev Console in the left menu.
  • On the Box Developer console, click Create New App, then Custom App.
  • In the Custom App popup, select Server Authentication (with JWT), enter a name in App name, and click Create.
  • On the app page, open the Configuration tab, check Manage Webhooks under Developer Actions, and click Save Changes.
  • Open the Authorization tab, click Review and Submit, enter a description in App Description (for example, Requesting Access), and click Submit.
  • In Box Admin Console, go to Apps, Custom App Manager, click View on your app, then Authorize and Authorize again.
  • Back in the Box Developer Console, open your app, click the Webhook tab, click Create Webhook, then V2.
  • On Create a Webhook, paste the ngrok URL in URL Address (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app).
  • For Content Type, click Choose an item and select a folder from your Box account.
  • Under File Triggers, check File Uploaded and click Create Webhook.

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Run webhooks with Box and ngrok

With the File Uploaded trigger, Box sends a notification to your app when you upload files to the chosen folder.
  • In Box, upload a file from your desktop to the folder you selected when creating the webhook.
Confirm your localhost app receives the FILE.UPLOADED 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 Box 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 the Box Developer Console, open your app, go to the Webhook tab, and click Manage Signature Keys.
  • On Manage Signature Keys, click Generate Key in Primary Key and click COPY to copy the primary key value.
  • Create a Traffic Policy file named box_policy.yml. Replace {your primary key} with the value you copied: 
    on_http_request:
  - actions:
      - type: verify-webhook
        config:
          provider: box
          secret: "{your primary key}"
  • Restart ngrok with the policy file: 
    ngrok http 3000 --traffic-policy-file box_policy.yml
  • Upload a file to the folder you selected for the webhook to trigger a request.
Your app should receive the request and log it in the terminal.