# boolean_smtp_mail_headers_normalized

> Fires after headers have been normalized, before they are written back onto the message.

Action · Tier B · Since 1.0.0



## Signature

```php
add_action( 'boolean_smtp_mail_headers_normalized', $callback, 10, 2 );
```

## Parameters

| Name | Type | Description |
| --- | --- | --- |
| `$headers` | `\BooleanSmtp\Services\Mailer\Headers\MailHeaders` | Normalized header bag. |
| `$message` | `\BooleanSmtp\Services\Mailer\MailMessage` | Message the headers belong to. |

## Fires in

- [app/Services/Mailer/BooleanSmtpMailPipeline.php:335](https://github.com/booleanpress/boolean-smtp-src/blob/main/app/Services/Mailer/BooleanSmtpMailPipeline.php#L335) — `BooleanSmtp\Services\Mailer\BooleanSmtpMailPipeline::applyHeaderPipeline()`

## Example

```php
add_action( 'boolean_smtp_mail_headers_normalized', function ( \BooleanSmtp\Services\Mailer\Headers\MailHeaders $headers, \BooleanSmtp\Services\Mailer\MailMessage $message ) {
    // React to the event.
}, 10, 2 );
```