Groundmail for WordPress

The official Groundmail plugin for WordPress. It sends every email WordPress and its plugins send with wp_mail() (password resets, new accounts, comment notifications, WooCommerce orders, contact forms) through the Groundmail email API over HTTPS.

• HTML and plain-text email, CC, BCC, Reply-To and custom headers
• Attachments and inline images
• Default or forced From email and name
• API key in the settings or in wp-config.php (GROUNDMAIL_API_KEY)
• A test email button and an optional log of the last 50 sends
• Keeps the filters and hooks other plugins rely on: wp_mail_from, wp_mail_from_name, wp_mail_content_type, phpmailer_init, wp_mail_failed, wp_mail_succeeded

Without an API key the plugin does nothing, and WordPress sends email the way it did before.

Requires WordPress 5.7 or later and PHP 7.4 or later. Licensed GPLv2 or later.

Install

1. Upload the groundmail folder to wp-content/plugins/ (or upload groundmail.zip under Plugins → Add New → Upload Plugin) and activate it.

2. In Groundmail, verify your sending domain and create an API key under API Keys. A send-only key is enough.

3. In WordPress, open Settings → Groundmail, paste the key and set the From email to an address on your verified domain. Or keep the key out of the database:

   // wp-config.php
   define( 'GROUNDMAIL_API_KEY', 'gm_your_key' );

4. Send a test email from the same page. delivered@simulator.groundmail.dev checks the connection without emailing a real inbox.

WooCommerce sends its emails with wp_mail(), so they go through Groundmail with no extra setup. Set the WooCommerce "From" address to your verified domain, or turn on Force From.

Filters

groundmail_email_body changes the request body for one email before it is sent, for example to add tags or a category:

add_filter( 'groundmail_email_body', function ( $body, $atts ) {
    $body['tags'] = array( array( 'name' => 'source', 'value' => 'wordpress' ) );
    return $body;
}, 10, 2 );

groundmail_email_sent fires after Groundmail accepts an email, with its id (msg_…) and the request body.

What the plugin sends

Only to https://api.groundmail.dev, and only once an API key is set: each email (sender, recipients, subject, content, attachments, custom headers) to POST /emails, and a key check (GET /emails?limit=1) when you save a new key. See the terms and privacy policy.

Development

composer install
composer test            # unit tests, no WordPress needed
bin/build-zip.sh         # dist/groundmail.zip, the files that ship

tests/e2e/run.py runs the plugin in a real WordPress against a local mock of the API; see the top of that file.