[Solution] Symfony SwiftMailer multiple recipients

You can use an “array” :

$to = array(
            "user1@gmail.com" => "User 1",
            "user2@gmail.com" => "User 2"
        );

Example :

$subject = "User";

        $to = array(
            "user1@gmail.com" => "User 1",
            "user2@gmail.com" => "User 2"
        );

        $from = "contact@become-developer.com";
        $name = "Become Developer";

        $body = "content";

$message = \Swift_Message::newInstance()
            ->setSubject($subject)
            ->setFrom($from)
            ->setTo($to)
            ->setBody($body)
            /*
             * If you also want to include a plaintext version of the message
            ->addPart(
                $this->renderView(
                    'Emails/registration.txt.twig',
                    array('name' => $name)
                ),
                'text/plain'
            )
            */
        ;

        // or, you can also fetch the mailer service this way
        // $this->get('mailer')->send($message);
        return $this->mailer->send($message);