dotkernel/dot-mail-outlook

Dotkernel Dot-Mail Outlook ESMTP service.

0.2 2025-08-19 10:49 UTC

Requires

• php: ~8.2.0 || ~8.3.0 || ~8.4.0
• ext-curl: *
• dotkernel/dot-dependency-injection: ^1.2.0
• dotkernel/dot-mail: ^5.1.5
• laminas/laminas-servicemanager: ^3.22 || ^4.0
• symfony/mailer: ^v7.1.6

Requires (Dev)

• laminas/laminas-coding-standard: ^3.1.0
• phpstan/phpstan: ^2.1
• phpstan/phpstan-phpunit: ^2.0
• phpunit/phpunit: ^10.5.46

MIT

• Dotkernel Team

• symfony
• microsoft
• outlook
• Office365
• dotkernel
• symfony-mailer
• esmtp
• xoauth2
• dot-mail

README

Dotkernel's Microsoft Outlook ESMTP email service, implementing the client credentials grant_type.

dot-mail-outlook is a wrapper on top of dotkernel/dot-mail

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Installation

Install dotkernel/dot-mail-outlook by executing the following Composer command:

composer require dotkernel/dot-mail-outlook

Register src/ConfigProvider.php in config/config.php by adding the following line:

\Dot\MailOutlook\ConfigProvider::class,

Configuration

Copy the dot-mail-outlook.local file to your autoload folder (or copy its contents to mail.global.php) and fill in the relevant information.

<?php

declare(strict_types=1);

$tenant = '';

return [
    'xoauth2_outlook' => [
        "tokenCacheFile"  => '',
        "tenant"          => $tenant,
        "access_code_url" => "https://login.microsoftonline.com/{$tenant}/oauth2/v2.0/token",
        "client_id"       => '',
        "client_secret"   => '',
        "scope"           => 'https://outlook.office.com/.default',
        "grant_type"      => 'client_credentials',
    ],
];

The dotkernel/dot-mail config file should be updated to make sure the necessary options are set:

• transport MUST be set to under the dot_mail.default.transport key.
• port MUST be set to 587 under the dot_mail.default.smtp_options.port key.
• tls MUST be set to STARTTLS under the dot_mail.default.smtp_options.tls key.
• host MUST be one of smtp-mail.outlook.com or smtp.office365.com under the dot_mail.default.smtp_options.host key.

Additional info

dotkernel/dot-mail-outlook makes use of SASL XOAUTH2 mechanism for use with the SMTP AUTH command.

To allow generating the bearer token in the background, without user input required, dot-mail-outlook implements the client credentials flow from Microsoft:

• Authenticate an IMAP, POP or SMTP connection using OAuth
• Microsoft identity platform and the OAuth 2.0 client credentials flow

Make sure to set all relevant permissions, give relevant tenant administrator consent and register the necessary service principals, as described in Microsoft's flow.