# Facebook Messenger Integration Guide

Integrating Facebook with Cloud Voice lets your agents read and respond to messages sent to a Facebook Page from within the Cloud Voice App, so there is no need to sign in to Facebook Messenger separately.

## Requirements

Make sure both sides of the integration meet the conditions below before you begin.

### Cloud Voice PBX

Your PBX (Private Branch Exchange, the phone system that hosts Cloud Voice) must meet these conditions:

- **Firmware**: Version `84.20.0.128` or later.
- **Domain name**: The PBX domain name must not contain underscore (`_`) characters. Because of a restriction on Facebook's platform, an underscore causes the messaging channel to fail authentication or stop receiving messages.
- **Domain certificate**: A valid domain certificate must be installed on the PBX.

:::note
If your Cloud PBX uses a custom root domain rather than one of the standard domains provided with Cloud Voice, install a valid domain certificate first. Otherwise the messaging channel will fail authentication or be unable to receive messages.
:::

### Facebook

- **Product**: Messenger Platform.
- **Accounts**:
  - A [Meta Developer account](https://developers.facebook.com/docs/development/register).

    :::note
    One Meta Developer account is enough to create multiple Meta apps for Facebook channel integration, and there is no limit to the number of Facebook channels you can add to the PBX.
    :::
  - A [Business Manager account (Business Portfolio)](https://www.facebook.com/business/help/1710077379203657?id=180505742745347).

    :::note
    After you create the Business Manager account, complete Meta's [business verification](https://www.facebook.com/business/help/2058515294227817?id=180505742745347).
    :::

## Limitations

Keep the following constraints of the Facebook messaging channel in mind.

| Item | Description |
|------|-------------|
| Message type | Text messages and multimedia messages are supported. The multimedia types allowed are determined by Facebook; see [Facebook supported media types](https://developers.facebook.com/docs/messenger-platform/reference/send-api#sample-request). |
| Messaging mechanism | Agents can receive and reply to **inbound** messages only. They cannot start a new messaging session with a Facebook user. |
| Message sending rate | Up to **40** messages per second. |
| File size | Up to **25 MB** per file. |
| File retention period | Files are retained for **72 hours**. |

:::caution
When you send a multimedia message such as an image, Facebook downloads the file from a link that the PBX provides. If you use an Allowed Country/Region IP access protection rule, make sure the country where the Facebook server is located is permitted, or the file transfer will fail.
:::

## Integration workflow

Complete the following steps to bring a Facebook Page online in Cloud Voice.

:::note
Do these steps in order. Create and configure the Facebook channel first (step 1), then test message delivery and submit the app for review (step 2).
:::

1. **[Set up a Facebook channel](/pbx/contact-center-guide/set-up-a-facebook-channel/)**: Create and configure a Meta app to integrate a Facebook Page.

2. **[Submit your app for review](/pbx/contact-center-guide/submit-app-for-review/)**: Test message delivery between the Facebook Page and the PBX, then submit your app for Meta review and switch it to Live mode.