> ## Documentation Index
> Fetch the complete documentation index at: https://ngrok.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Facebook Messenger Webhooks

> Develop and test Facebook Messenger webhooks from localhost.

This guide shows you how to use ngrok to receive Facebook Messenger webhooks on your localhost app.

By integrating ngrok with Facebook Messenger, you can:

* Develop and test Facebook Messenger webhooks locally without deploying to a public environment or setting up HTTPS.
* Inspect and troubleshoot requests from Facebook Messenger in real time via the inspection UI and API.
* Modify and replay Facebook Messenger webhook requests with a single click instead of reproducing events manually in your account.
* Secure your app with Facebook Messenger webhook validation provided by ngrok.
  Invalid requests are blocked by ngrok before reaching your app.

## What you'll need

* An [ngrok account](https://ngrok.com/signup) and your [authtoken](https://dashboard.ngrok.com/get-started/your-authtoken).
* The [ngrok agent](https://ngrok.com/download) installed.
* [Node.js](https://nodejs.org/) installed (for the sample app, or use your own app).
* A Facebook account.

<Note>
  This integration requires an ngrok Pay-as-you-go plan because Facebook validates your ngrok domain.
</Note>

## 1. Start your app

For this tutorial, you can use the [sample Node.js app on GitHub](https://github.com/ngrok/ngrok-webhook-nodejs-sample).

To install the sample, run the following in a terminal:

```bash theme={null}
git clone https://github.com/ngrok/ngrok-webhook-nodejs-sample.git
cd ngrok-webhook-nodejs-sample
npm install
```

Then start the app:

```bash theme={null}
npm run startFacebook
```

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.

* Copy [your ngrok authtoken](https://dashboard.ngrok.com/get-started/your-authtoken) from the dashboard.

<Tip>
  The ngrok agent uses your authtoken to authenticate when you start a tunnel.
</Tip>

* In the dashboard, expand **Gateway** and click **Domains**.

<Tip>
  If you don't have an ngrok Pay-as-you-go plan, subscribe by clicking **Update Subscription** and following the procedure.
</Tip>

* On the **Domains** page, click **+ Create Domain** or **+ New Domain**.
* In the **Domain** pane, enter a value in the **Domain** field (for example, `myexample.ngrok.app`) and click **Continue**.

<Tip>
  Make sure your domain is available.
</Tip>

* Close the **Start a Tunnel** pane and then close the **Domain** pane.

* Start ngrok with your domain:

  ```bash theme={null}
  ngrok http 3000 --url myexample.ngrok.app
  ```

* Copy the URL ngrok displays.
  Your app is now exposed at that URL for use with Facebook Messenger.

## 3. Configure Facebook Messenger to send webhooks

Facebook Messenger can send webhook requests to your app when events occur in your account.
To register for those events you need a Facebook page associated with your account; create one before continuing.

* Sign in to [Meta for Developers](https://developers.facebook.com/).
* Click **My Apps** and then **Create App** on the **Apps** page.
* On **Create an App**, select **Business** and click **Next**.
* On **Provide basic information**, enter a **Display name** (for example, `My Example App`), ensure your email is in **App contact email**, and click **Create App**.

<Tip>
  Facebook may ask for your password in the **Please Re-enter Your Password** popup.
</Tip>

* On the app page, click **Add Product** and then **Set up** inside the **Messenger** tile.
* On **Messenger Settings**, click **Add Callback URL** in the **Webhooks** section.
* In the **Edit Callback URL** popup, enter your ngrok URL with `/webhook` at the end in the **Callback URL** field (for example, `https://myexample.ngrok.app/webhook`).
* Enter `12345` in the **Verify token** field and click **Verify and save**.
* Confirm your localhost app receives the validation post request in the terminal.
* Back on **Messenger Settings**, click **Add or remove Pages** in the **Webhooks** section.
* In the page that opens, sign in to Facebook, select a page, click **Next**, then **Done**, and click **OK** when the link confirmation appears.
* Close the new browser window that shows your Facebook page.
* Under **Messenger** in the left menu, click **Settings**, scroll to **Webhooks**, click **Add subscription** for your page, select all subscription fields, and click **Save**.
* In **Built-in NLP**, select your page in **Select a Page** and turn the slider on.
* At the top of the app page, set **App Mode** to **Live**.

### Run webhooks with Facebook Messenger and ngrok

To trigger webhook calls from Facebook Messenger to your app:

* In [Meta for Developers](https://developers.facebook.com/), go to **Webhooks** under **Products**.
* On the **Webhooks** page, select **Page** in the combo box, find a subscription field you subscribed to, and click **Test**.
* In the **Field Sample** popup, click **Send to My Server**.

Confirm your localhost app receives the test message and logs both headers and body in the terminal.

<Tip>
  Facebook sends different request body contents depending on the events you selected when registering the webhook.
</Tip>

To test with a real message, open the Facebook page you linked to your webhook and send a message to another user.
You can also sign in with another Facebook account, open your page, and send a message via Messenger.

Your app should receive the request and log it in the terminal.

### Inspecting requests

ngrok's [Traffic Inspector](https://dashboard.ngrok.com/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.

<Info>
  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](https://dashboard.ngrok.com/settings) to capture complete request and response data.
</Info>

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 Facebook Messenger webhook so only that traffic reaches your app.

<Note>
  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](/pricing-limits/traffic-policy-unit-pricing/) for details.
</Note>

To add verification:

* In [Meta for Developers](https://developers.facebook.com/), go to **My Apps**, then **Settings** and **Basic**.

* On the **Basic Settings** page, click **Show** next to **App secret** and copy the value.

* Create a Traffic Policy file named `messenger_policy.yml`.
  Replace `{your app secret}` with the value you copied:

  ```yaml theme={null}
  on_http_request:
    - name: "Facebook Messenger Webhooks"
      actions:
        - type: "webhook-validation"
          config:
            provider: "facebook_messenger"
            secret: "{your app secret}"
  ```

* Restart ngrok with the policy file:

  ```bash theme={null}
  ngrok http 3000 --traffic-policy-file messenger_policy.yml
  ```

* Send a message from the Facebook page linked to your webhook to trigger a request.

Your app should receive the request and log it in the terminal.