Reliable email delivery for WordPress.
Features email logging, queue management, backup failover, and a modern dashboard.
Polar SMTP Mailer provides a complete email delivery solution:
- β 100% Free & Open Source - No premium tiers or feature locks
- β Email Logging - Complete history with search, filter, export
- β Backup SMTP Failover - Automatic switch when primary fails
- β Email Queue - Background processing with priority & retry
- β 15+ Provider Presets - Gmail, Outlook, SendGrid, Mailgun, and more
- β Password Encryption - AES-256-CBC with WordPress salts
- β GDPR Privacy Tools - Exporter, eraser, anonymization
- β Modern Dashboard - Statistics, charts, quick actions
- β Self-Healing Database - Automatic table creation & repair
- β Clean Uninstall Option - Remove all data on deletion
| Feature | Description |
|---|---|
| π§ 15+ SMTP Providers | Gmail, Outlook, Yahoo, SendGrid, Mailgun, Amazon SES, Hostinger & more |
| π Email Logging | Complete history with search, filter, export (CSV/JSON) |
| π Email Queue | Background processing with priority & retry logic |
| π Backup SMTP | Automatic failover when primary fails |
| π‘οΈ Enterprise Security | AES-256 encryption, rate limiting, CSRF protection |
| π GDPR Compliant | Privacy exporter, eraser, and anonymization |
| π¨ Modern Dashboard | Statistics, charts, and quick actions |
| βΏ Accessible | WCAG AA compliant, screen reader friendly |
| Provider | Host | Port (TLS) | Port (SSL) |
|---|---|---|---|
| Gmail / Google Workspace | smtp.gmail.com | 587 | 465 |
| Outlook / Microsoft 365 | smtp.office365.com | 587 | - |
| Yahoo Mail | smtp.mail.yahoo.com | 587 | 465 |
| Zoho Mail | smtp.zoho.com | 587 | 465 |
| Hostinger | smtp.hostinger.com | 465 (SSL) | 465 |
| SendGrid | smtp.sendgrid.net | 587 | 465 |
| Mailgun | smtp.mailgun.org | 587 | 465 |
| Amazon SES | email-smtp.[region].amazonaws.com | 587 | 465 |
| Brevo (Sendinblue) | smtp-relay.brevo.com | 587 | 465 |
| Postmark | smtp.postmarkapp.com | 587 | 465 |
| SparkPost | smtp.sparkpostmail.com | 587 | - |
| SMTP.com | send.smtp.com | 587 | 465 |
| Elastic Email | smtp.elasticemail.com | 2525 | - |
| Mailjet | in-v3.mailjet.com | 587 | 465 |
| Pepipost (Netcore) | smtp.pepipost.com | 587 | 465 |
| Type | Port | Recommendation |
|---|---|---|
| TLS | 587 | β Recommended (STARTTLS) |
| SSL | 465 | Good alternative |
| None | 25 |
- Complete History - Track all sent, failed, and queued emails
- View Details - Full email content, headers, CC/BCC, attachments
- Search & Filter - Find by recipient, subject, status, or date range
- One-Click Actions - View, Resend, Delete individual logs
- Bulk Operations - Delete multiple logs at once
- Export - Download as CSV or JSON
- Auto Cleanup - Configurable retention (default: 30 days)
| Feature | Description |
|---|---|
| Background Processing | Via WP-Cron, no server impact |
| Batch Size | Configurable (default: 10) |
| Processing Interval | Configurable (default: 5 min) |
| Priority Support | 1-10 scale for urgent emails |
| Retry Logic | Up to 3 attempts on failure |
| Lock Mechanism | Prevents duplicate processing |
| Test Bypass | Test emails skip queue |
| Feature | Implementation |
|---|---|
| Password Encryption | AES-256-CBC with WordPress AUTH_KEY |
| CSRF Protection | Nonces on all forms and AJAX |
| Authorization | manage_options capability required |
| Rate Limiting | 5 test emails per 10 minutes |
| Input Sanitization | All inputs sanitized |
| Output Escaping | All output escaped (XSS prevention) |
| SQL Injection | Prepared statements everywhere |
- β WordPress Privacy Exporter integration
- β WordPress Privacy Eraser integration
- β Email anonymization option
- β Content exclusion from logs
- β Auto-suggested privacy policy text
- β Configurable data retention
- π Email statistics (Today, Week, Month, All-time)
- π Visual charts with daily trends
- β‘ Quick actions (Test email, View logs, Settings)
- π Connection health indicator
- π¬ Real-time queue counter
- π± Fully responsive design
# Download and extract to wp-content/plugins/
git clone https://github.com/boopathirbk/polar-smtp-mailer.git- Plugins β Add New β Upload Plugin
- Upload the ZIP file
- Activate and configure at Polar SMTP β Settings
- Navigate to Polar SMTP β Settings
- Select your SMTP provider from dropdown
- Enter your credentials (username/password)
- Click Test Connection to verify
- Send a test email to confirm delivery
- Save Settings
| Requirement | Version |
|---|---|
| WordPress | 6.0+ |
| PHP | 7.4+ |
| MySQL | 5.6+ / MariaDB 10.0+ |
| OpenSSL | Required for encryption |
add_filter( 'psm_smtp_providers', function( $providers ) {
$providers['my_provider'] = array(
'name' => 'My Custom Provider',
'host' => 'smtp.example.com',
'port' => 587,
'encryption' => 'tls',
'auth' => true,
);
return $providers;
});add_filter( 'psm_bypass_queue', function( $bypass, $atts ) {
if ( strpos( $atts['subject'], 'Urgent' ) !== false ) {
return true; // Send immediately
}
return $bypass;
}, 10, 2 );| Dashboard | Settings |
|---|---|
| Email Logs | Test Email |
|---|---|
- Compliance: Removed promotional/comparative language from readme files.
- Compliance: Added External Services section for SMTP provider documentation.
- Compliance: Fixed global variable naming conventions in admin views.
- Compliance: Fixed hook naming conventions.
- UI: Enhanced email log modal with From Email tracking and grid layout.
- UI: Improved modal responsiveness for mobile devices.
- Fix: Backup SMTP connection test and result styling.
- Fix: Uninstall cleanup.
- Removed debug logging for compliance.
- Fixed HTML email display in log viewer.
- Fixed empty recipient validation in queue.
- Improved PHP 8.2 compatibility.
- Security fixes (Encryption, SQL prep).
- Fixed race condition in queue processing.
- TLS 1.2/1.3 support.
Initial Release:
- SMTP configuration with 15+ provider presets
- Email logging with View, Resend, Delete actions
- Email queue with background processing
- Backup SMTP failover
- GDPR-compliant privacy features
- Modern admin dashboard with statistics
- AES-256-CBC password encryption
- Rate limiting and security features
- Hostinger SMTP sender fix
- Self-healing database
- Clean uninstall option
- Full i18n support
- Fork the repository
- Create feature branch (
git checkout -b feature/Amazing) - Commit changes (
git commit -m 'Add Amazing Feature') - Push to branch (
git push origin feature/Amazing) - Open a Pull Request
GPL v2 or later - see LICENSE for details.
Boopathi R.
- LinkedIn: @boopathirb
- GitHub: @boopathirbk
If you find this plugin useful, consider buying me a coffee!
Made with β€οΈ for the WordPress community