[ 'db' => [ 'class' => 'yii\db\Connection', 'dsn' => 'mysql:host=localhost;dbname=database', 'username' => 'root', 'password' => '', 'charset' => 'utf8', ], 'mailer' => [ 'class' => 'yii\swiftmailer\Mailer', 'viewPath' => '@common/mail', // send all mails to a file by default. You have to set // 'useFileTransport' to false and configure a transport // for the mailer to send real emails. 'useFileTransport' => true, ], ], ];