class Cake\Mailer\Mailer(string|array|null $profile = null)

Mailer is a convenience class for sending email. With this class you can send email from any place inside of your application.

Basic Usage

First of all, you should ensure the class is loaded:

use Cake\Mailer\Mailer;

After you’ve loaded Mailer, you can send an email with the following:

$mailer = new Mailer('default');
$mailer->setFrom(['[email protected]' => 'My Site'])
    ->setTo('[email protected]')
    ->deliver('My message');

Since Mailer’s setter methods return the instance of the class, you are able to set its properties with method chaining.

Mailer has several methods for defining recipients - setTo(), setCc(), setBcc(), addTo(), addCc() and addBcc(). The main difference being that the first three will overwrite what was already set and the latter will just add more recipients to their respective field:

$mailer = new Mailer();
$mailer->setTo('[email protected]', 'To Example');
$mailer->addTo('[email protected]', 'To2 Example');
// The email's To recipients are: [email protected] and [email protected]
$mailer->setTo('[email protected]', 'ToTest Example');
// The email's To recipient is: [email protected]

Choosing the Sender

When sending email on behalf of other people, it’s often a good idea to define the original sender using the Sender header. You can do so using setSender():

$mailer = new Mailer();
$mailer->setSender('[email protected]', 'MyApp emailer');


It’s also a good idea to set the envelope sender when sending mail on another person’s behalf. This prevents them from getting any messages about deliverability.


Mailer profiles and email transport settings are defined in your application’s configuration files. The Email and EmailTransport keys define mailer profiles and email transport configurations respectively. During application bootstrap configuration settings are passed from Configure into the Mailer and TransportFactory classes using setConfig(). By defining profiles and transports, you can keep your application code free of configuration data, and avoid duplication that makes maintenance and deployment more difficult.

To load a predefined configuration, you can use the setProfile() method or pass it to the constructor of Mailer:

$mailer = new Mailer();

// Or in constructor
$mailer = new Mailer('default');

Instead of passing a string which matches a preset configuration name, you can also just load an array of options:

$mailer = new Mailer();
$mailer->setProfile(['from' => '[email protected]', 'transport' => 'my_custom']);

// Or in constructor
$mailer = new Mailer(['from' => '[email protected]', 'transport' => 'my_custom']);

Configuration Profiles

Defining delivery profiles allows you to consolidate common email settings into re-usable profiles. Your application can have as many profiles as necessary. The following configuration keys are used:

  • 'from': Mailer or array of sender. See Mailer::setFrom().

  • 'sender': Mailer or array of real sender. See Mailer::setSender().

  • 'to': Mailer or array of destination. See Mailer::setTo().

  • 'cc': Mailer or array of carbon copy. See Mailer::setCc().

  • 'bcc': Mailer or array of blind carbon copy. See Mailer::setBcc().

  • 'replyTo': Mailer or array to reply the e-mail. See Mailer::setReplyTo().

  • 'readReceipt': Mailer address or an array of addresses to receive the receipt of read. See Mailer::setReadReceipt().

  • 'returnPath': Mailer address or an array of addresses to return if have some error. See Mailer::setReturnPath().

  • 'messageId': Message ID of e-mail. See Mailer::setMessageId().

  • 'subject': Subject of the message. See Mailer::setSubject().

  • 'message': Content of message. Do not set this field if you are using rendered content.

  • 'priority': Priority of the email as numeric value (usually from 1 to 5 with 1 being the highest).

  • 'headers': Headers to be included. See Mailer::setHeaders().

  • 'viewRenderer': If you are using rendered content, set the view classname. See ViewBuilder::setClassName().

  • 'template': If you are using rendered content, set the template name. See ViewBuilder::setTemplate().

  • 'theme': Theme used when rendering template. See ViewBuilder::setTheme().

  • 'layout': If you are using rendered content, set the layout to render. See ViewBuilder::setTemplate().

  • 'autoLayout': If you want to render a template without layout, set this field to false. See ViewBuilder::disableAutoLayout().

  • 'viewVars': If you are using rendered content, set the array with variables to be used in the view. See Mailer::setViewVars().

  • 'attachments': List of files to attach. See Mailer::setAttachments().

  • 'emailFormat': Format of email (html, text or both). See Mailer::setEmailFormat().

  • 'transport': Transport configuration name. See Configuring Transports.

  • 'log': Log level to log the email headers and message. true will use LOG_DEBUG. See Using Levels. Note that logs will be emitted under the scope named email. See also Logging Scopes.

  • 'helpers': Array of helpers used in the email template. ViewBuilder::setHelpers()/ViewBuilder::addHelpers().


The values of above keys using Mailer or array, like from, to, cc, etc will be passed as first parameter of corresponding methods. The equivalent for: $mailer->setFrom('', 'My Site') would be defined as 'from' => ['' => 'My Site'] in your config

Setting Headers

In Mailer you are free to set whatever headers you want. Do not forget to put the X- prefix for your custom headers.

See Mailer::setHeaders() and Mailer::addHeaders()

Sending Templated Emails

Emails are often much more than just a simple text message. In order to facilitate that, CakePHP provides a way to send emails using CakePHP’s view layer.

The templates for emails reside in a special folder templates/email of your application. Mailer views can also use layouts and elements just like normal views:

$mailer = new Mailer();
            ->setTo('[email protected]')
            ->setFrom('[email protected]')


The above would use templates/email/html/welcome.php for the view and templates/layout/email/html/fancy.php for the layout. You can send multipart templated email messages as well:

$mailer = new Mailer();
            ->setTo('[email protected]')
            ->setFrom('[email protected]')


This would use the following template files:

  • templates/email/text/welcome.php

  • templates/layout/email/text/fancy.php

  • templates/email/html/welcome.php

  • templates/layout/email/html/fancy.php

When sending templated emails you have the option of sending either text, html or both.

You can set all view related config using the view builder instance got by Mailer::viewBuilder() similar to how you do the same in controller.

You can set view variables with Mailer::setViewVars():

$mailer = new Mailer('templated');
$mailer->setViewVars(['value' => 12345]);

Or you can use the view builder methods ViewBuilder::setVar() and ViewBuilder::setVars().

In your email templates you can use these with:

<p>Here is your value: <b><?= $value ?></b></p>

You can use helpers in emails as well, much like you can in normal template files. By default only the HtmlHelper is loaded. You can load additional helpers using the ViewBuilder::addHelpers() method:

$mailer->viewBuilder()->addHelpers(['Html', 'Custom', 'Text']);

When adding helpers be sure to include ‘Html’ or it will be removed from the helpers loaded in your email template.


In versions prior to 4.3.0, you will need to use setHelpers() instead.

If you want to send email using templates in a plugin you can use the familiar plugin syntax to do so:

$mailer = new Mailer();

The above would use template and layout from the Blog plugin as an example.

In some cases, you might need to override the default template provided by plugins. You can do this using themes:


This allows you to override the new_comment template in your theme without modifying the Blog plugin. The template file needs to be created in the following path: templates/plugin/TestTheme/plugin/Blog/email/text/new_comment.php.

Sending Attachments


You can attach files to email messages as well. There are a few different formats depending on what kind of files you have, and how you want the filenames to appear in the recipient’s mail client:

  1. Array: $mailer->setAttachments(['/full/file/path/file.png']) will attach this file with the name file.png..

  2. Array with key: $mailer->setAttachments(['photo.png' => '/full/some_hash.png']) will attach some_hash.png with the name photo.png. The recipient will see photo.png, not some_hash.png.

  3. Nested arrays:

        'photo.png' => [
            'file' => '/full/some_hash.png',
            'mimetype' => 'image/png',
            'contentId' => 'my-unique-id'

    The above will attach the file with different mimetype and with custom Content ID (when set the content ID the attachment is transformed to inline). The mimetype and contentId are optional in this form.

    3.1. When you are using the contentId, you can use the file in the HTML body like <img src="cid:my-content-id">.

    3.2. You can use the contentDisposition option to disable the Content-Disposition header for an attachment. This is useful when sending ical invites to clients using outlook.

    3.3 Instead of the file option you can provide the file contents as a string using the data option. This allows you to attach files without needing file paths to them.

Relaxing Address Validation Rules


If you are having validation issues when sending to non-compliant addresses, you can relax the pattern used to validate email addresses. This is sometimes necessary when dealing with some ISPs:

$mailer = new Mailer('default');

// Relax the email pattern, so you can send
// to non-conformant addresses.

Sending Messages Quickly

Sometimes you need a quick way to fire off an email, and you don’t necessarily want to setup a bunch of configuration ahead of time. Cake\Mailer\Email::deliver() is intended for that purpose.

You can create your configuration using Cake\Mailer\Email::config(), or use an array with all options that you need and use the static method Email::deliver(). Example:

Email::deliver('[email protected]', 'Subject', 'Message', ['from' => '[email protected]']);

This method will send an email to “”, from “” with subject “Subject” and content “Message”.

The return of deliver() is a Cake\Mailer\Email instance with all configurations set. If you do not want to send the email right away, and wish to configure a few things before sending, you can pass the 5th parameter as false.

The 3rd parameter is the content of message or an array with variables (when using rendered content).

The 4th parameter can be an array with the configurations or a string with the name of configuration in Configure.

If you want, you can pass the to, subject and message as null and do all configurations in the 4th parameter (as array or using Configure). Check the list of configurations to see all accepted configs.

Sending Emails from CLI

When sending emails within a CLI script (Shells, Tasks, …) you should manually set the domain name for Mailer to use. It will serve as the host name for the message id (since there is no host name in a CLI environment):

// Results in message ids like ``<[email protected]>`` (valid)
// Instead of `<UUID@>`` (invalid)

A valid message id can help to prevent emails ending up in spam folders.

Creating Reusable Emails

Until now we have seen how to directly use the the Mailer class to create and send one emails. But main feature of mailer is to allow creating reusable emails throughout your application. They can also be used to contain multiple email configurations in one location. This helps keep your code DRYer and keeps email configuration noise out of other areas in your application.

In this example we will be creating a Mailer that contains user-related emails. To create our UserMailer, create the file src/Mailer/UserMailer.php. The contents of the file should look like the following:

namespace App\Mailer;

use Cake\Mailer\Mailer;

class UserMailer extends Mailer
    public function welcome($user)
            ->setSubject(sprintf('Welcome %s', $user->name))
                ->setTemplate('welcome_mail'); // By default template with same name as method name is used.

    public function resetPassword($user)
            ->setSubject('Reset password')
            ->setViewVars(['token' => $user->token]);

In our example we have created two methods, one for sending a welcome email, and another for sending a password reset email. Each of these methods expect a user Entity and utilizes its properties for configuring each email.

We are now able to use our UserMailer to send out our user-related emails from anywhere in our application. For example, if we wanted to send our welcome email we could do the following:

namespace App\Controller;

use Cake\Mailer\MailerAwareTrait;

class UsersController extends AppController
    use MailerAwareTrait;

    public function register()
        $user = $this->Users->newEmptyEntity();
        if ($this->request->is('post')) {
            $user = $this->Users->patchEntity($user, $this->request->getData())
            if ($this->Users->save($user)) {
                $this->getMailer('User')->send('welcome', [$user]);
        $this->set('user', $user);

If we wanted to completely separate sending a user their welcome email from our application’s code, we can have our UserMailer subscribe to the Model.afterSave event. By subscribing to an event, we can keep our application’s user-related classes completely free of email-related logic and instructions. For example, we could add the following to our UserMailer:

public function implementedEvents()
    return [
        'Model.afterSave' => 'onRegistration'

public function onRegistration(EventInterface $event, EntityInterface $entity, ArrayObject $options)
    if ($entity->isNew()) {
        $this->send('welcome', [$entity]);

You can now register the mailer as an event listener and the onRegistration() method will be invoked every time the Model.afterSave event is fired:

// attach to Users event manager


For information on how to register event listener objects, please refer to the Registering Listeners documentation.

Configuring Transports

Email messages are delivered by transports. Different transports allow you to send messages via PHP’s mail() function, SMTP servers, or not at all which is useful for debugging. Configuring transports allows you to keep configuration data out of your application code and makes deployment simpler as you can simply change the configuration data. An example transport configuration looks like:

// In config/app.php
'EmailTransport' => [
    // Sample Mail configuration
    'default' => [
        'className' => 'Mail',
    // Sample SMTP configuration
    'gmail' => [
        'host' => '',
        'port' => 587,
        'username' => '[email protected]',
        'password' => 'secret',
        'className' => 'Smtp',
        'tls' => true

Transports can also be configured at runtime using TransportFactory::setConfig():

use Cake\Mailer\TransportFactory;

// Define an SMTP transport
TransportFactory::setConfig('gmail', [
    'host' => 'ssl://',
    'port' => 465,
    'username' => '[email protected]',
    'password' => 'secret',
    'className' => 'Smtp'

You can configure SSL SMTP servers, like Gmail. To do so, put the ssl:// prefix in the host and configure the port value accordingly. You can also enable TLS SMTP using the tls option:

use Cake\Mailer\TransportFactory;

TransportFactory::setConfig('gmail', [
    'host' => '',
    'port' => 587,
    'username' => '[email protected]',
    'password' => 'secret',
    'className' => 'Smtp',
    'tls' => true

The above configuration would enable TLS communication for email messages.

To configure your mailer to use a specific transport you can use Cake\Mailer\Mailer::setTransport() method or have the transport in your configuration:

// Use a named transport already configured using TransportFactory::setConfig()

// Use a constructed object.
$mailer->setTransport(new \Cake\Mailer\Transport\DebugTransport());


You will need to have access for less secure apps enabled in your Google account for this to work: Allowing less secure apps to access your account.


To use SSL + SMTP, you will need to have the SSL configured in your PHP install.

Configuration options can also be provided as a DSN string. This is useful when working with environment variables or PaaS providers:

TransportFactory::setConfig('default', [
    'url' => 'smtp://[email protected]:[email protected]:587?tls=true',

When using a DSN string you can define any additional parameters/options as query string arguments.

static Cake\Mailer\Mailer::drop($key)

Once configured, transports cannot be modified. In order to modify a transport you must first drop it and then reconfigure it.

Creating Custom Transports

You are able to create your custom transports for situations such as send email using services like SendGrid, MailGun or Postmark. To create your transport, first create the file src/Mailer/Transport/ExampleTransport.php (where Example is the name of your transport). To start, your file should look like:

namespace App\Mailer\Transport;

use Cake\Mailer\AbstractTransport;
use Cake\Mailer\Message;

class ExampleTransport extends AbstractTransport
    public function send(Message $message): array
        // Do something.

You must implement the method send(Message $message) with your custom logic.

Sending emails without using Mailer

The Mailer is a higher level abstraction class which acts as a bridge between the Cake\Mailer\Message, Cake\Mailer\Renderer and Cake\Mailer\AbstractTransport classes to configure emails with a fluent interface.

If you want you can use these classes directly with the Mailer too.

For example:

$render = new \Cake\Mailer\Renderer();

$message = new \Cake\Mailer\Message();
    ->setFrom('[email protected]')
    ->setTo('[email protected]')

$transport = new \Cake\Mailer\Transport\MailTransport();
$result = $transport->send($message);

You can even skip using the Renderer and set the message body directly using Message::setBodyText() and Message::setBodyHtml() methods.

Testing Mailers

To test mailers, add Cake\TestSuite\EmailTrait to your test case. The MailerTrait uses PHPUnit hooks to replace your application’s email transports with a proxy that intercepts email messages and allows you to do assertions on the mail that would be delivered.

Add the trait to your test case to start testing emails, and load routes if your emails need to generate URLs:

namespace App\Test\TestCase\Mailer;

use App\Mailer\WelcomeMailer;
use App\Model\Entity\User;

use Cake\TestSuite\EmailTrait;
use Cake\TestSuite\TestCase;

class WelcomeMailerTestCase extends TestCase
    use EmailTrait;

    public function setUp(): void

Let’s assume we have a mailer that delivers welcome emails when a new user registers. We want to check that the subject and body contain the user’s name:

// in our WelcomeMailerTestCase class.
public function testName()
    $user = new User([
        'name' => 'Alice Alittea',
        'email' => '[email protected]',
    $mailer = new WelcomeMailer();
    $mailer->send('welcome', [$user]);

    $this->assertMailContainsText('Hi ' . $user->name);
    $this->assertMailContainsText('Welcome to CakePHP!');

Assertion methods

The Cake\TestSuite\EmailTrait trait provides the following assertions:

// Asserts an expected number of emails were sent

// Asserts that no emails were sent

// Asserts an email was sent to an address

// Asserts an email was sent from an address
$this->assertMailSentFrom([$emailAddress => $displayName]);

// Asserts an email contains expected contents

// Asserts an email contains expected html contents

// Asserts an email contains expected text contents

// Asserts an email contains the expected value within an Message getter (for example, "subject")
$this->assertMailSentWith($expected, $parameter);

// Asserts an email at a specific index was sent to an address
$this->assertMailSentToAt($at, $address);

// Asserts an email at a specific index was sent from an address
$this->assertMailSentFromAt($at, $address);

// Asserts an email at a specific index contains expected contents
$this->assertMailContainsAt($at, $contents);

// Asserts an email at a specific index contains expected html contents
$this->assertMailContainsHtmlAt($at, $contents);

// Asserts an email at a specific index contains expected text contents
$this->assertMailContainsTextAt($at, $contents);

// Asserts an email contains an attachment

// Asserts an email at a specific index contains the expected value within an Message getter (for example, "cc")
$this->assertMailSentWithAt($at, $expected, $parameter);

// Asserts an email contains a substring in the subject.
$this->assertMailSubjectContains('Free Offer');

// Asserts an email at the specific index contains a substring in the subject.
$this->assertMailSubjectContainsAt(1, 'Free Offer');