Mailtrap w/ EE

config.php

<?php

$config['mail_protocol'] = 'smtp';
$config['smtp_server'] = 'mailtrap.io';
$config['smtp_username'] = 'YOUR_MAILTRAP_INBOX_USERNAME';
$config['smtp_password'] = 'YOUR_MAILTRAP_INBOX_PASSWORD';
$config['email_newline'] = "\r\n";
$config['email_crlf'] = "\r\n";
$config['email_smtp_port'] = TRUE;
$config['smtp_port'] = '2525';