README

A modern, driver-based email library for CodeIgniter 4.

Postal replaces CodeIgniter 4's monolithic Email class with a clean transport-driver architecture: compose a message once and send it through SMTP, Sendmail, PHP mail(), Amazon SES, a log, or a failover chain — without changing your application code. It keeps the familiar CI4 email API working for a painless migration, and it's fully testable without ever sending a real message.

Status: Public beta (0.x). The API is stable and ready for use; breaking changes before 1.0 will be rare and called out clearly in the changelog.

Documentation

lonnieezell.github.io/postal — full reference, guides, and configuration options for every transport.

Why Postal?

Driver-based transports — swap how mail is delivered via config, not code.
Drop-in friendly — existing service('email') calls keep working through a compatibility adapter.
Amazon SES — deliver through SesV2 with SigV4 signing; no SMTP relay required.
DKIM signing — sign outbound messages at the library level with a one-line config addition, no application code changes.
Failover chain — wrap any number of mailers in a priority-ordered fallback so a provider outage doesn't drop mail.
Suppression lists & unsubscribe — bind your own suppression list to silently filter recipients before send, and auto-inject List-Unsubscribe headers.
Inline image embedding — local paths and data: URIs in HTML are automatically rewritten to cid: attachments.
Zero required dependencies — PHP standard extensions only. No database, no queue, no view renderer needed to send mail.
Built for testing — a fake transport and expressive assertions let you verify mail in PHPUnit without touching the network.
Mailable classes — reusable, class-based emails with browser preview support in development.

Requirements

PHP 8.2+
CodeIgniter 4.7+
Extensions: ext-openssl, ext-mbstring
ext-curl + aws/aws-sdk-php for the Amazon SES transport (optional)

Installation

composer require myth/postal

CodeIgniter auto-discovers the package — no manual wiring required.

php spark email:test you@example.com   # send a test message via the default transport

Quick Start

Compose and send

<?php

use Myth\Postal\Email;

$email = (new Email())
    ->from('you@example.com', 'Your Name')
    ->to('user@example.com')
    ->subject('Welcome aboard')
    ->html('<p>Glad to have you with us.</p>');

$result = service('mailer')->send($email);

if ($result->success) {
    log_message('info', 'Sent message ' . $result->messageId);
}

send() returns a SendResult carrying success, the provider messageId, any error, and the raw provider response.

Send through a named transport

<?php

service('mailer')->mailer('ses')->send($email);   // use the 'ses' mailer for this send

Mailable classes

For reusable, testable messages, extend Mailable:

<?php

use Myth\Postal\Mailable;

class WelcomeEmail extends Mailable
{
    public function __construct(private User $user)
    {
        parent::__construct();
    }

    protected function build(): void
    {
        $this->to($this->user->email)
             ->subject('Welcome aboard')
             ->html(view('emails/welcome', ['user' => $this->user]));
    }
}

(new WelcomeEmail($user))->send();

Scaffold one with:

php spark make:mailable WelcomeEmail

Backward-compatible API

Existing CodeIgniter email code keeps working unchanged via service('email'):

<?php

$email = service('email');
$email->setTo('user@example.com');
$email->setSubject('Hello');
$email->setMessage('<p>Hi there.</p>');
$email->send();

Transports

Transport	Config name	Available
SMTP	`smtp`	✅
Sendmail	`sendmail`	✅
PHP `mail()`	`mail`	✅
Log	`log`	✅
Null	`null`	✅
Fake (testing)	—	✅
Amazon SES	`ses`	✅
Failover	`failover`	✅
DKIM signing (decorator)	—	✅
Mailgun	`mailgun`	Planned
Postmark	`postmark`	Planned
Resend	`resend`	Planned

Configuration

Transports are defined as named mailers in Config\Email, with a $default chosen per environment:

<?php

public string $default = match (ENVIRONMENT) {
    'production' => 'ses',
    'testing'    => 'null',
    default      => 'log',
};

public array $mailers = [
    'smtp' => [
        'transport'  => 'smtp',
        'host'       => 'localhost',
        'port'       => 587,
        'encryption' => 'tls',
        'username'   => '',
        'password'   => '',
    ],
    'log'  => ['transport' => 'log'],
    'null' => ['transport' => 'null'],
];

See the full documentation for every transport's configuration reference, DKIM setup, SES credentials, and more.

Events

Postal fires events through CodeIgniter's Events system at each stage of the send pipeline:

Event	Fired	Cancellable
`email.composing`	before defaults/suppression are applied	No
`email.sending`	just before the transport sends	Yes
`email.sent`	after a successful send	No
`email.failed`	after a failed send	No
`email.suppressed`	per recipient removed by a suppression list	No

Returning false from an email.sending listener cancels the send. Event emission can be disabled with Config\Email::$fireEvents = false.

Testing

Swap in the fake transport and assert against what would have been sent — no network, no real mail:

<?php

use Myth\Postal\Mailer;

$fake = Mailer::fake();

(new WelcomeEmail($user))->send();

$fake->assertSent(WelcomeEmail::class);
$fake->assertSentTo($user->email);
$fake->assertSent(fn ($message) => str_contains($message->subject, 'Welcome'));
$fake->assertSentCount(1);

Contributing

Contributions are welcome. The project ships with a full toolchain (PHPUnit, php-cs-fixer, PHPStan, Rector) runnable locally or in Docker:

composer test        # run the test suite
composer ci          # style + static analysis + tests (run before opening a PR)
composer cs-fix      # auto-fix coding style

Docker equivalents are available for every command by prefixing docker: (e.g. composer docker:test), and docker compose up starts a dev container with all required extensions. A pre-commit hook (installed on composer install) lints and auto-formats staged PHP files.

Please ensure composer ci passes and new behavior is covered by tests before submitting a pull request.

License

Released under the MIT License.

myth / postal

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