Omailer v3.0.0

What Omailer does

Replaces the default wp_mail() transport with a configurable SMTP stack, then layers a full email marketing suite on top.

Getting set up

Plugin constants

Defined in omailer.php at load time.

Database schema

All tables use the prefix {wpdb->prefix}om_. Use OM_DB::table( 'name' ) to get the full table name safely.

Settings reference

Stored in a single serialised array option: om_settings.

PHP$settings  = get_option( 'om_settings', [] );
$from_name = $settings['from_name'] ?? get_bloginfo('name');

Using shortcodes

[om_subscribe]
[om_subscribe title="Join our list" show_name="yes" list="2" tags="newsletter"]
[om_subscribe style="popup" trigger="exit"]
[om_subscribe style="slide-in" trigger="scroll" delay="50"]

We have [om_subscriber_count] subscribers.

Global helper functions

PHPom_send_email( string $to, string $subject, string $body, array $headers = [] ): bool

om_send_email(
    'user@example.com',
    'Your Order Confirmation',
    '<p>Thanks for your order!</p>',
    [ 'Reply-To: orders@mysite.com' ]
);

PHPom_subscribe( string $email, array $data = [] ): int|false
// $data: first_name, last_name, list_id, source, meta (field_key => value)

$sub_id = om_subscribe( 'jane@example.com', [
    'first_name' => 'Jane',
    'list_id'    => 3,
    'source'     => 'checkout',
    'meta'       => [ 'company' => 'Acme Corp' ],
] );

PHPom_unsubscribe( string $email ): bool

PHPom_add_tag( int $subscriber_id, string $tag_slug ): void
om_remove_tag( int $subscriber_id, string $tag_slug ): void

om_add_tag( 42, 'vip' );

Hooks & filters

PHPadd_action( 'om_subscriber_bounced', function( string $email, string $provider ) {
    error_log( "Bounce from {$provider} for {$email}" );
}, 10, 2 );

// Tag a WooCommerce customer on order completion
add_action( 'woocommerce_order_status_completed', function( int $order_id ) {
    $order = wc_get_order( $order_id );
    $sub   = OM_Subscriber::get_by_email( $order->get_billing_email() );
    if ( $sub ) om_add_tag( (int) $sub->id, 'customer' );
} );

PHPadd_filter( 'wp_mail', function( array $args ): array {
    $args['headers'][] = 'Bcc: archive@mycompany.com';
    return $args;
} );

AJAX endpoints

Managing subscribers

PHPOM_Subscriber::insert( array $data ): int|false
OM_Subscriber::get_by_email( string $email ): object|null
OM_Subscriber::get_by_id( int $id ): object|null
OM_Subscriber::update( int $id, array $data ): void
OM_Subscriber::count( string $status = 'subscribed' ): int
OM_Subscriber::get_all( array $args ): array   // args: search, status, list_id, per_page, page
OM_Subscriber::add_to_list( int $subscriber_id, int $list_id ): void

email,first_name,last_name,status
john@example.com,John,Doe,subscribed
jane@example.com,Jane,,subscribed

Tags & segmentation

PHPOM_Tags::get_all(): array                              // includes subscriber_count
OM_Tags::create( string $name ): int|false            // slug auto-generated
OM_Tags::delete( int $tag_id ): void                  // removes all assignments
OM_Tags::add_to_subscriber( int $sub_id, int $tag_id ): void
// fires: do_action( 'om_tag_added', $subscriber_id, $tag_id )
OM_Tags::remove_from_subscriber( int $sub_id, int $tag_id ): void
OM_Tags::get_for_subscriber( int $sub_id ): array
OM_Tags::add_by_slug( int $sub_id, string $slug ): void  // creates tag if needed

Custom fields & merge tags

PHP$html         = '<p>Hi {{first_name}},</p><p>Your company: {{company}}</p>';
$subscriber   = OM_Subscriber::get_by_email( 'jane@example.com' );
$personalised = OM_Custom_Fields::apply_merge_tags( $html, $subscriber );

Mailing lists

Subscribers can belong to one or more named lists. The "General" list is created on activation and cannot be deleted.

PHPOM_Subscriber::create_list( string $name, string $description = '' ): int
OM_Subscriber::delete_list( int $list_id ): void         // subscribers NOT deleted
OM_Subscriber::add_to_list( int $subscriber_id, int $list_id ): void
OM_Subscriber::remove_from_list( int $subscriber_id, int $list_id ): void

Building campaigns

PHPOM_Campaign::get_all(): array
OM_Campaign::get_by_id( int $id ): object|null
OM_Campaign::save( array $data ): int|false
OM_Campaign::delete( int $id ): void
OM_Campaign::duplicate( int $id ): int|false    // creates a draft copy

// Dispatch immediately
OM_Sender::dispatch( int $campaign_id ): void

The cron event om_send_scheduled fires hourly and processes campaigns with status = 'scheduled' and scheduled_at <= NOW(). All merge tags are replaced per subscriber at send time.

Automation sequences

PHPadd_action( 'user_purchase', function( int $subscriber_id ) {
    OM_Automation::trigger( 'wp_hook', $subscriber_id, 'user_purchase' );
} );

// Cron: om_process_automations every 5 minutes, processes up to 100 active runs

Double opt-in

When double_optin is enabled, new subscribers are created with status = 'pending' and a random token. A confirmation email links to:

/?om_action=confirm&token={confirmation_token}

On visit: status → subscribed, token cleared, confirmed_at set, OM_Automation::trigger( 'subscribe', ... ) fires.

Bounce & complaint webhooks

Register these URLs with your email provider. Supported: mailgun, sendgrid, postmark.

https://yoursite.com/omailer/webhook/{provider}/

Spam score checker

PHP$result = OM_Spam_Score::analyse( string $subject, string $body ): array;
// Returns: [ 'score' => 12, 'grade' => 'B', 'issues' => [ [...], ... ] ]

Deliverability tools

PHP$results = OM_Deliverability::check_domain( 'yourdomain.com' );
// Returns: [ 'domain', 'checked', 'score' => 85,
//            'spf' => [...], 'dkim' => [...], 'dmarc' => [...] ]

PHP$window = OM_Deliverability::get_best_send_window( int $days = 30 ): array;
// Returns: [ 'suggestion' => '...', 'top_windows' => [ ['day','hour','label','opens'], ... ] ]

Email builder

JSOmBuilder.init( 'my-container-id' );
const html = OmBuilder.exportHTML();
OmBuilder.setBlocks( OmBuilder.getBlocks() );

window.omBuilderExport = function( html ) {
    document.getElementById('om_html_content').value = html;
};

Gutenberg block

Block name: omailer/subscribe-form — registered in assets/js/om-gutenberg.js. Dynamic block: save() returns null, output rendered server-side.

Public subscribe forms

assets/js/om-public.js is enqueued on all front-end pages. Handles fetch-based inline submissions, overlay lifecycle, custom field serialisation, and auto-close after subscribe.

SMTP configuration

Connections are stored in om_smtp_connections as an associative array keyed by UUID.

PHPOM_SMTP::get_connections(): array
OM_SMTP::get_connection( string $id ): array|null
OM_SMTP::get_primary_id(): string|null
OM_SMTP::get_backup_id(): string|null
OM_SMTP::get_presets(): array

Built-in presets: Gmail, Outlook / Office 365, Yahoo, SendGrid, Mailgun, Amazon SES, Postmark, SparkPost, Brevo, Zoho Mail, Custom.

On primary connection failure, Omailer retries with the backup connection. If both fail, falls back to PHP's mail().

Smart email routing

OM_Smart_Routing routes outbound emails to specific SMTP connections based on recipient domain, email type, or source plugin. Rules evaluate top-to-bottom; first match wins.

• Recipient domain — send all @bigcorp.com emails via a dedicated connection
• Email type — transactional, notification, or marketing
• Source plugin — e.g. woocommerce, contact-form-7

Email log

All outbound emails are logged — subject, recipient, status, source plugin, timestamps. Body content is optional via om_log_settings['log_body'].

PHPOM_Email_Log::get_logs( array $args ): array      // args: search, status, per_page, page
OM_Email_Log::get_status_counts(): array
OM_Email_Log::resend( int $log_id ): bool
OM_Email_Log::export( string $format ): void       // 'csv' or 'json', streams download

Logs are purged after 90 days (configurable via om_log_retention_days).

Failure alerts

Sends an admin email when an outbound email fails. Settings in om_alert_settings:

Email controls

Toggle WordPress core email notifications on/off without code — new user registration, password reset, auto-updates, comment notifications, and more.

PHPOM_Email_Controls::get_controls_list(): array
OM_Email_Controls::get_settings(): array

Performance & queue

When async mode is enabled, all wp_mail() calls are stored in om_email_queue and dispatched in the background by cron.

Misc settings

JavaScript APIs

JSOM.ajax_url        // admin-ajax.php URL
OM.nonce           // om_admin nonce
OM.export_url      // CSV export URL
OM.log_export_csv  // Log CSV export URL
OM.log_export_json // Log JSON export URL

What's changed