The Mailer Component¶

The Mailer component helps sending emails.

If you’re using the Symfony Framework, read the Symfony Framework Mailer documentation.

Installation¶

1	$ composer require symfony/mailer

Note

If you install this component outside of a Symfony application, you must require the vendor/autoload.php file in your code to enable the class autoloading mechanism provided by Composer. Read this article for more details.

Usage¶

The Mailer component has two main classes: a Transport and the Mailer itself:

use Symfony\Component\Mailer\Mailer;
use Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport;

$transport = new EsmtpTransport('localhost');
$mailer = new Mailer($transport);
$mailer->send($email);

The $email object is created via the Mime component.

Transport¶

The only transport that comes pre-installed is SMTP.

Below is the list of other popular providers with built-in support:

Service	Install with
Amazon SES	`composer require symfony/amazon-mailer`
Gmail	`composer require symfony/google-mailer`
MailChimp	`composer require symfony/mailchimp-mailer`
Mailgun	`composer require symfony/mailgun-mailer`
Postmark	`composer require symfony/postmark-mailer`
SendGrid	`composer require symfony/sendgrid-mailer`

For example, suppose you want to use Google’s Gmail SMTP server. First, install it:

1	$ composer require symfony/google-mailer

Then, use the SMTP Gmail transport:

use Symfony\Component\Mailer\Bridge\Google\Transport\GmailSmtpTransport;
use Symfony\Component\Mailer\Mailer;

$transport = new GmailSmtpTransport('user', 'pass');
$mailer = new Mailer($transport);
$mailer->send($email);

Each provider provides up to 3 transports: standard SMTP, HTTP (it uses the provider’s API but the body is created by the mailer component), API (it uses the full API of the provider with no control over the body creation – features might be limited as well).

The mailer component provides a convenient way to create a transport from a DSN:

use Symfony\Component\Mailer\Transport;

$transport = Transport::fromDsn($dsn);

Where $dsn depends on the provider you want to use. For plain SMTP, use smtp://user:pass@example.com or sendmail+smtp://default to use the sendmail binary. To disable the transport, use null://null.

For third-party providers, refer to the following table:

Provider	SMTP	HTTP	API
Amazon SES	ses+smtp://ACCESS_KEY:SECRET_KEY@default	ses+https://ACCESS_KEY:SECRET_KEY@default	ses+api://ACCESS_KEY:SECRET_KEY@default
Google Gmail	gmail+smtp://USERNAME:PASSWORD@default	n/a	n/a
Mailchimp Mandrill	mandrill+smtp://USERNAME:PASSWORD@default	mandrill+https://KEY@default	mandrill+api://KEY@default
Mailgun	mailgun+smtp://USERNAME:PASSWORD@default	mailgun+https://KEY:DOMAIN@default	mailgun+api://KEY:DOMAIN@default
Postmark	postmark+smtp://ID:ID@default	n/a	postmark+api://KEY@default
Sendgrid	sendgrid+smtp://apikey:KEY@default	n/a	sendgrid+api://KEY@default

Caution

If your credentials contain special characters, you must URL-encode them. For example, the DSN ses+smtp://ABC1234:abc+12/345@default should be configured as ses+smtp://ABC1234:abc%2B12%2F345@default

Note

When using SMTP, the default timeout for sending a message before throwing an exception is the value defined in the default_socket_timeout PHP.ini option.

New in version 5.1: The usage of default_socket_timeout as the default timeout was introduced in Symfony 5.1.

Instead of choosing a specific protocol, you can also let Symfony pick the best one by omitting it from the scheme: for instance, mailgun://KEY:DOMAIN@default is equivalent to mailgun+https://KEY:DOMAIN@default.

If you want to override the default host for a provider (to debug an issue using a service like requestbin.com), change default by your host:

mailgun+https://KEY:DOMAIN@example.com
mailgun+https://KEY:DOMAIN@example.com:99

Note that the protocol is always HTTPs and cannot be changed.

High Availability¶

Symfony’s mailer supports high availability via a technique called “failover” to ensure that emails are sent even if one mailer server fails .

A failover transport is configured with two or more transports and the failover keyword:

$dsn = 'failover(postmark+api://ID@default sendgrid+smtp://KEY@default)';

The mailer will start using the first transport. If the sending fails, the mailer won’t retry it with the other transports, but it will switch to the next transport automatically for the following deliveries.

Load Balancing¶

Symfony’s mailer supports load balancing via a technique called “round-robin” to distribute the mailing workload across multiple transports .

A round-robin transport is configured with two or more transports and the roundrobin keyword:

$dsn = 'roundrobin(postmark+api://ID@default sendgrid+smtp://KEY@default)'

The mailer will start using a randomly selected transport and if it fails, it will retry the same delivery with the next transports until one of them succeeds (or until all of them fail).

New in version 5.1: The random selection of the first transport was introduced in Symfony 5.1. In previous Symfony versions the first transport was always selected first.

TLS Peer Verification¶

By default, SMTP transports perform TLS peer verification. This behavior is configurable with the verify_peer option. Although it’s not recommended to disable this verification for security reasons, it can be useful while developing the application or when using a self-signed certificate:

$dsn = 'smtp://user:pass@smtp.example.com?verify_peer=false'

New in version 5.1: The verify_peer option was introduced in Symfony 5.1.

Sending emails asynchronously¶

If you want to send emails asynchronously, install the Messenger component.

1	$ composer require symfony/messenger

Then, instantiate and pass a MessageBus as a second argument to Mailer:

use Symfony\Component\Mailer\Envelope;
use Symfony\Component\Mailer\Mailer;
use Symfony\Component\Mailer\Messenger\MessageHandler;
use Symfony\Component\Mailer\Messenger\SendEmailMessage;
use Symfony\Component\Mailer\Transport;
use Symfony\Component\Messenger\Handler\HandlersLocator;
use Symfony\Component\Messenger\MessageBus;
use Symfony\Component\Messenger\Middleware\HandleMessageMiddleware;
use Symfony\Component\Mime\Address;

$dsn = 'change-dsn-accordingly';

$transport = Transport::fromDsn($dsn);
$handler = new MessageHandler($transport);

$bus = new MessageBus([
    new HandleMessageMiddleware(new HandlersLocator([
        SendEmailMessage::class => [$handler],
    ])),
]);

$mailer = new Mailer($transport, $bus);
$mailer->send($email);

// you can pass an optional Envelope
$mailer->send($email, new Envelope(
    new Address('sender@example.com'),
    [
        new Address('recipient@example.com'),
    ]
));

Learn More¶

To learn more about how to use the mailer component, refer to the Symfony Framework Mailer documentation.