Bedrock mu-plugin: redirect all emails to specified email when on staging environment. Change the email as needed!

hhdev-wp-redir-all-emails-on-staging.php

<?php
// Bedrock mu-plugin: redirect all emails to developer email on staging site
// Don't forget to set your email address!

add_filter( 'wp_mail', 'hhdev_staging_email_filter', 10, 1 );

function hhdev_staging_email_filter( $args ) {

	if (getenv('WP_ENV') == 'staging') {

		// Get original To address
		$original_to = $args['to'];

		// Send to developer only
		$args['to'] = 'your@emailadres.nl';

		// Show original To address in message for debug
		$args['message'] = sprintf( "Staging environment: Message would originally be sent to: [%s]\n", $original_to ) . $args['message'];

	}

	return $args;

}