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

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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:
  • Copy the URL ngrok displays. Your app is now exposed at that URL for use with Brex.

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3. Configure Brex to send webhooks

Brex registers webhooks through its API. Follow Brex’s Webhooks API documentation to create a webhook, using an API token with write access to the resources you want to receive events for (this example uses Users). Create the webhook, setting its URL to your ngrok URL:
Replace YOUR_TOKEN_HERE with your API token and YOUR_NGROK_URL with your ngrok URL (for example, https://1a2b-3c4d-5e6f-7g8h-9i0j.ngrok.app). A successful response returns HTTP 200 with "status": "ACTIVE".

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Run webhooks with Brex and ngrok

The USER_UPDATED event fires when a user in your account changes. To trigger a webhook call, invite a new user to your Brex account. Confirm your app receives the event and logs the headers and body in the terminal.
If Brex doesn’t send the notification, check the invitee’s email and accept the invitation to complete the user creation.

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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 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

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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 Brex 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:
  • Get your webhook secret from the Brex API:
    Replace YOUR_TOKEN_HERE with the token you copied when configuring the webhook. The response includes JSON with a "secret" value; copy it.
  • Create a Traffic Policy file named brex_policy.yml. Replace {your webhook secret} with the secret value you copied:
  • Restart ngrok with the policy file:
  • Create a new user in the Brex Dashboard (and have the invite accepted) to trigger a webhook.
Your app should receive the request and log it in the terminal.