# boolean_smtp_microsoft_graph_base_url

> Filters the Microsoft Graph API base URL.

Filter · Tier B · Since 1.0.0

Allows targeting a national cloud deployment (for example Microsoft Graph for US Government or operated by 21Vianet) instead of the global endpoint.

## Signature

```php
add_filter( 'boolean_smtp_microsoft_graph_base_url', $callback, 10, 1 );
```

## Parameters

| Name | Type | Description |
| --- | --- | --- |
| `$baseUrl` | `string` | Default Microsoft Graph base URL. |

**Returns** `string` — The filtered base URL.

## Fires in

- [app/Services/Mailer/Api/MicrosoftGraphMailSender.php:1134](https://github.com/booleanpress/boolean-smtp-src/blob/main/app/Services/Mailer/Api/MicrosoftGraphMailSender.php#L1134) — `BooleanSmtp\Services\Mailer\Api\MicrosoftGraphMailSender::graphResourceUrl()`

## Example

```php
add_filter( 'boolean_smtp_microsoft_graph_base_url', function ( string $baseUrl ) {
    return $baseUrl;
}, 10, 1 );
```