Frumbik

WordPress uses the PHP <code>mail()</code> function by default, which often results in emails being marked as spam or not delivered at all. Frumbik SMTP replaces the default mail function with authenticated SMTP or API-based email delivery through your chosen provider.
Connect Gmail, SendGrid, Amazon SES, or any SMTP server — and all emails WordPress sends will be properly authenticated, encrypted, and delivered.
<h4>Key Features</h4>
Frumbik SMTP provides the following capabilities, all included in the free version:
🔄 Automatic Failover — If your primary provider goes down, emails automatically route to your backup provider.
📊 Dashboard — Real-time delivery stats, success rates, and charts. See what is happening with your emails at a glance.
📋 Complete Email Log — Every email logged with status, timestamps, headers, and source plugin. Search, filter, resend, or export — all from one screen.
🔐 Strong Security — AES-256-CBC encryption for all credentials. Security scoring dashboard with actionable recommendations.
⚡ Background Queue — High-traffic site? Queue emails for async delivery so your pages load fast while emails send in the background.
🎯 Smart Routing — Route WooCommerce emails through SendGrid, contact forms through Mailgun, and newsletters through Amazon SES — all automatically.
<h4>9 Providers, One Plugin</h4>
Connect to any email service without installing separate add-ons:
<ul>
<li>Other SMTP — Any SMTP server (Gmail, Outlook, Yahoo, your hosting, custom servers)</li>
<li>SendGrid — Transactional email API by Twilio</li>
<li>Mailgun — Email API by Sinch</li>
<li>Postmark — Transactional email delivery by ActiveCampaign</li>
<li>Brevo (formerly Sendinblue) — Marketing and transactional email</li>
<li>SparkPost — Email delivery by MessageBird</li>
<li>Amazon SES — AWS Simple Email Service (v2 API with Signature v4)</li>
<li>Microsoft 365 / Outlook — Microsoft Graph API with OAuth 2.0</li>
<li>Gmail API — Google Gmail API with OAuth 2.0</li>
</ul>
All providers are included in the plugin.
<h4>Core Features</h4>
📨 Reliable Email Delivery
<ul>
<li>Replace WordPress’s unreliable <code>wp_mail()</code> with authenticated SMTP or native API connections</li>
<li>Supports TLS and SSL encryption protocols</li>
<li>Proper SPF, DKIM, and DMARC alignment through your provider</li>
<li>Works with any WordPress theme, plugin, or page builder</li>
</ul>
📋 Comprehensive Email Logging
<ul>
<li>Every outgoing email logged automatically — sent, failed, or queued</li>
<li>Full details: recipients, subject, body, headers, attachments, timestamps</li>
<li>Automatic source detection — know which plugin triggered each email</li>
<li>One-click resend for failed or bounced emails</li>
<li>CSV export with advanced search and filtering</li>
<li>Configurable log retention (auto-cleanup old logs)</li>
</ul>
🔄 Multi-Connection & Failover
<ul>
<li>Configure multiple mail providers simultaneously</li>
<li>Automatic failover — if Provider A fails, Provider B takes over instantly</li>
<li>No manual intervention needed. No lost emails during outages.</li>
<li>Connection health monitoring with success rate tracking</li>
</ul>
🎯 Smart Routing Rules
<ul>
<li>Route emails to different providers based on conditions:
<ul>
<li>Recipient email address or domain</li>
<li>Email subject containing specific keywords</li>
<li>The WordPress plugin that triggered the email</li>
</ul>
</li>
<li>Example: WooCommerce orders → SendGrid, contact forms → Mailgun</li>
<li>Priority ordering with drag-free interface</li>
</ul>
⚡ Email Queue (Async Sending)
<ul>
<li>Queue emails for background delivery via WP-Cron</li>
<li>Pages load faster — no waiting for SMTP connections during page loads</li>
<li>Failed emails automatically retried with exponential backoff</li>
<li>Configurable batch size and retry limits</li>
<li>Real-time queue dashboard with cancel/retry controls</li>
</ul>
🔔 Failure Notifications
<ul>
<li>Get alerted instantly when emails fail to send</li>
<li>4 notification channels: Email, Slack, Discord, Telegram</li>
<li>Per-event subscription — choose exactly which events trigger alerts</li>
<li>Notification history with delivery status tracking</li>
</ul>
🔐 Security
<ul>
<li>AES-256-CBC encryption for all stored credentials (passwords, API keys, OAuth tokens)</li>
<li>Security Score Dashboard — real-time security posture with actionable fix recommendations</li>
<li>Dedicated encryption key support via <code>wp-config.php</code></li>
<li>Rate limiting on all REST API endpoints</li>
<li>Six custom WordPress capabilities for role-based access control</li>
<li>Full audit log tracking every configuration change</li>
<li>CSRF protection, nonce verification, input sanitization throughout</li>
</ul>
🧙 Setup Wizard
<ul>
<li>Guided 7-step wizard for first-time configuration</li>
<li>Automatic import from WP Mail SMTP, Post SMTP, Fluent SMTP, and Easy WP SMTP</li>
<li>Provider presets with pre-filled configuration fields</li>
<li>Built-in connection test with real-time feedback</li>
</ul>
🛠️ Import / Export & Tools
<ul>
<li>Export your complete configuration as a JSON file (settings, connections, routing rules)</li>
<li>Import on another site to replicate your setup instantly</li>
<li>Debug Info page with system diagnostics for troubleshooting</li>
<li>Multisite-compatible import/export</li>
</ul>
🖥️ Modern Admin Interface
<ul>
<li>React-powered single-page application — fast and responsive</li>
<li>Real-time dashboard with delivery charts and statistics</li>
<li>Responsive design for desktop, tablet, and mobile</li>
<li>Built with WordPress accessibility standards (WCAG 2.1)</li>
<li>Full internationalization support (i18n-ready)</li>
</ul>
🌐 Multisite Ready
<ul>
<li>Full WordPress Multisite support out of the box</li>
<li>Network-wide or per-site configuration</li>
<li>Network admin management panel</li>
<li>Settings propagation across all network sites</li>
</ul>
<h4>For Developers</h4>
<ul>
<li>Hooks & Filters — 30+ action and filter hooks for complete customization</li>
<li>IoC Container — Laravel-inspired dependency injection container</li>
<li>PSR-4 Autoloading — Clean, namespaced codebase via Composer</li>
<li>REST API — Full REST API for headless or programmatic management</li>
<li>Extensible Providers — Add custom mail providers by implementing <code>MailProviderInterface</code></li>
<li>Strategy Pattern — Clean architecture with strategy, repository, and service provider patterns</li>
</ul>
<h3>External services</h3>
This plugin connects to third-party email delivery services and notification platforms to send emails and alerts on your behalf. No data is sent to any service unless you explicitly configure and enable that provider or notification channel in the plugin settings.
<h4>Gmail API (Google)</h4>
When configured as a mail provider, this plugin connects to the Gmail API to send emails using your Google account via OAuth 2.0.
<ul>
<li>Endpoints: <code>https://gmail.googleapis.com</code>, <code>https://accounts.google.com</code>, <code>https://oauth2.googleapis.com</code></li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), OAuth tokens for authentication</li>
<li>When: each time WordPress sends an email through this provider, and during OAuth authentication</li>
<li><a href="https://policies.google.com/privacy" rel="nofollow ugc">Google Privacy Policy</a></li>
<li><a href="https://policies.google.com/terms" rel="nofollow ugc">Google Terms of Service</a></li>
</ul>
<h4>Microsoft 365 / Outlook (Microsoft Graph API)</h4>
When configured as a mail provider, this plugin connects to the Microsoft Graph API to send emails using your Microsoft 365 or Outlook account via OAuth 2.0.
<ul>
<li>Endpoints: <code>https://graph.microsoft.com</code>, <code>https://login.microsoftonline.com</code></li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), OAuth tokens for authentication</li>
<li>When: each time WordPress sends an email through this provider, and during OAuth authentication</li>
<li><a href="https://privacy.microsoft.com/en-us/privacystatement" rel="nofollow ugc">Microsoft Privacy Statement</a></li>
<li><a href="https://www.microsoft.com/en-us/servicesagreement" rel="nofollow ugc">Microsoft Services Agreement</a></li>
</ul>
<h4>SendGrid (Twilio)</h4>
When configured as a mail provider, this plugin sends emails through the SendGrid API.
<ul>
<li>Endpoint: <code>https://api.sendgrid.com/v3</code></li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), API key for authentication</li>
<li>When: each time WordPress sends an email through this provider</li>
<li><a href="https://www.twilio.com/en-us/legal/privacy" rel="nofollow ugc">Twilio Privacy Policy</a></li>
<li><a href="https://www.twilio.com/en-us/legal/tos" rel="nofollow ugc">Twilio Terms of Service</a></li>
</ul>
<h4>Mailgun (Sinch)</h4>
When configured as a mail provider, this plugin sends emails through the Mailgun API.
<ul>
<li>Endpoints: <code>https://api.mailgun.net/v3</code> (US region) or <code>https://api.eu.mailgun.net/v3</code> (EU region)</li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), API key for authentication</li>
<li>When: each time WordPress sends an email through this provider</li>
<li><a href="https://www.mailgun.com/legal/privacy-policy/" rel="nofollow ugc">Mailgun Privacy Policy</a></li>
<li><a href="https://www.mailgun.com/legal/terms/" rel="nofollow ugc">Mailgun Terms of Service</a></li>
</ul>
<h4>Brevo (formerly Sendinblue)</h4>
When configured as a mail provider, this plugin sends emails through the Brevo API.
<ul>
<li>Endpoint: <code>https://api.brevo.com/v3</code></li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), API key for authentication</li>
<li>When: each time WordPress sends an email through this provider</li>
<li><a href="https://www.brevo.com/legal/privacypolicy/" rel="nofollow ugc">Brevo Privacy Policy</a></li>
<li><a href="https://www.brevo.com/legal/termsofuse/" rel="nofollow ugc">Brevo Terms of Use</a></li>
</ul>
<h4>SparkPost (MessageBird)</h4>
When configured as a mail provider, this plugin sends emails through the SparkPost API.
<ul>
<li>Endpoints: <code>https://api.sparkpost.com/api/v1</code> (US) or <code>https://api.eu.sparkpost.com/api/v1</code> (EU)</li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), API key for authentication</li>
<li>When: each time WordPress sends an email through this provider</li>
<li><a href="https://www.sparkpost.com/policies/privacy/" rel="nofollow ugc">SparkPost Privacy Policy</a></li>
<li><a href="https://www.sparkpost.com/policies/tou/" rel="nofollow ugc">SparkPost Terms of Use</a></li>
</ul>
<h4>Postmark (ActiveCampaign)</h4>
When configured as a mail provider, this plugin sends emails through the Postmark API.
<ul>
<li>Endpoint: <code>https://api.postmarkapp.com</code></li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), server API token for authentication</li>
<li>When: each time WordPress sends an email through this provider</li>
<li><a href="https://postmarkapp.com/privacy-policy" rel="nofollow ugc">Postmark Privacy Policy</a></li>
<li><a href="https://postmarkapp.com/terms-of-service" rel="nofollow ugc">Postmark Terms of Service</a></li>
</ul>
<h4>Amazon SES (Amazon Web Services)</h4>
When configured as a mail provider, this plugin sends emails through the Amazon SES v2 API using AWS Signature v4 authentication.
<ul>
<li>Endpoint: <code>https://email.{region}.amazonaws.com</code> (region depends on your configuration)</li>
<li>Data sent: email content (recipients, subject, body, headers, attachments), signed with AWS access key credentials</li>
<li>When: each time WordPress sends an email through this provider</li>
<li><a href="https://aws.amazon.com/privacy/" rel="nofollow ugc">AWS Privacy Notice</a></li>
<li><a href="https://aws.amazon.com/service-terms/" rel="nofollow ugc">AWS Service Terms</a></li>
</ul>
<h4>Telegram Bot API</h4>
When configured as a notification channel, this plugin sends failure alerts to a Telegram chat using the Telegram Bot API.
<ul>
<li>Endpoint: <code>https://api.telegram.org/bot{token}/sendMessage</code></li>
<li>Data sent: notification messages containing email failure details (recipient, subject, error message, timestamp)</li>
<li>When: each time a configured notification event occurs (e.g., email delivery failure)</li>
<li><a href="https://telegram.org/privacy" rel="nofollow ugc">Telegram Privacy Policy</a></li>
<li><a href="https://telegram.org/tos" rel="nofollow ugc">Telegram Terms of Service</a></li>
</ul>
<h4>Slack</h4>
When configured as a notification channel, this plugin sends failure alerts to a Slack channel using incoming webhooks.
<ul>
<li>Endpoint: user-configured Slack webhook URL (<code>https://hooks.slack.com/services/...</code>)</li>
<li>Data sent: notification messages containing email failure details (recipient, subject, error message, timestamp)</li>
<li>When: each time a configured notification event occurs (e.g., email delivery failure)</li>
<li><a href="https://slack.com/trust/privacy/privacy-policy" rel="nofollow ugc">Slack Privacy Policy</a></li>
<li><a href="https://slack.com/terms-of-service" rel="nofollow ugc">Slack Terms of Service</a></li>
</ul>
<h4>Discord</h4>
When configured as a notification channel, this plugin sends failure alerts to a Discord channel using webhooks.
<ul>
<li>Endpoint: user-configured Discord webhook URL (<code>https://discord.com/api/webhooks/...</code>)</li>
<li>Data sent: notification messages containing email failure details (recipient, subject, error message, timestamp)</li>
<li>When: each time a configured notification event occurs (e.g., email delivery failure)</li>
<li><a href="https://discord.com/privacy" rel="nofollow ugc">Discord Privacy Policy</a></li>
<li><a href="https://discord.com/terms" rel="nofollow ugc">Discord Terms of Service</a></li>
</ul>

Frumbik SMTP

Send WordPress emails via SMTP or API providers (SendGrid, SES, Gmail, M365) with smart routing, failover, email logging, and queue.

CherryPick Studios

Surbma

This plugin is created especially for Multisite Networks. You can define all variables in the wp-config.php file and it will be valid for all sites in a Multisite. So this is not for a site-by-site configuration plugin. You can install it on a single WordPress install also and it will work perfectly. But if you install it in a Multisite Network, you can only network activate it!
This plugin is working with all SMTP servers and services, like Mailgun, SendGrid, Mandrill, Amazon SES and others.
Required variables:
<ul>
<li><code>SURBMA_SMTP_HOST</code> – External SMTP server.</li>
<li><code>SURBMA_SMTP_USER</code> – User for the SMTP account.</li>
<li><code>SURBMA_SMTP_PASSWORD</code> – Password for the SMTP account.</li>
</ul>
Optional variables:
<ul>
<li><code>SURBMA_SMTP_PORT</code> – Port number for the SMTP server.</li>
<li><code>SURBMA_SMTP_SECURE</code> – Choose SSL or TLS, if necessary for your SMTP server.</li>
<li><code>SURBMA_SMTP_FROM</code> – From email address for all outgoing emails.</li>
<li><code>SURBMA_SMTP_FROMNAME</code> – From name for all outgoing emails.</li>
</ul>
Example configuration:
<pre><code> define('SURBMA_SMTP_HOST','smtp.mailgun.org');
 define('SURBMA_SMTP_USER','postmaster@surbma.com');
 define('SURBMA_SMTP_PASSWORD','bb2b************************4133');
</code></pre>
You can put these lines everywhere before the line, that says: “That’s It. Pencils down”
Do you want to contribute or help improving this plugin?
You can find it on GitHub: <a href="https://github.com/Surbma/surbma-smtp" rel="nofollow ugc">https://github.com/Surbma/surbma-smtp</a>
You can find my other plugins and projects on GitHub:
<a href="https://github.com/Surbma" rel="nofollow ugc">https://github.com/Surbma</a>
Please feel free to contribute, help or recommend any new features for my plugins, themes and other projects.
Do you want to know more about me?
Visit my webpage: <a href="http://surbma.com/" rel="nofollow ugc">Surbma.com</a>

Surbma | SMTP

External SMTP mail configuration via global variables in wp-config.php.

Frumbik SMTP vs Surbma | SMTP