Kelune SMTP – SMTP Mailer, Email Log, Fallback & Delivery Reports

Description

WordPress email delivery through SMTP, Amazon SES, Mailgun or SendGrid, with logs, fallback and health checks

Kelune SMTP takes over WordPress email and sends it through a connection you configure — classic SMTP, or an API provider such as Amazon SES, Mailgun or SendGrid. Every message is logged, so you can see what was sent, what failed, and why, and resend anything that did not arrive.

Every feature listed below is included and fully functional. Kelune SMTP stores all data in your own WordPress database and contacts an external service only when you configure a connection for it (see the “External services” section below). Nothing is ever sent to the plugin author.

Kelune SMTP is an independent plugin and is not affiliated with, endorsed by or sponsored by Amazon Web Services, Twilio SendGrid or Mailgun. Amazon SES, Mailgun and SendGrid are trademarks of their respective owners, named here only to identify the services a connection can send through.

👇 Helpful Links to Get Started

📬 Contact Us | 🛟 Support Forum | 🐙 Source Code

❤️ Features

• Multiple connections — configure as many senders as you need and keep them side by side.
• Four providers — SMTP, Amazon SES, Mailgun, and SendGrid, each with its own credential form.
• Routing by From address — every connection owns one sender address, and mail from that address goes out through it.
• Default and fallback — a default connection handles everything unrouted, and an optional fallback takes over when the primary fails.
• Email log — status, provider, recipients, subject, headers, and the provider’s own response for every message.
• Resend — send a logged message again, to its original recipients or to different ones.
• Retention — prune logged messages automatically after a number of days you choose.
• Health checks — a daily check per active connection, plus an on-demand check from the connections screen.
• Test email — send a test through any connection from anywhere in the dashboard.
• Kill switch — turn routing off and WordPress goes straight back to its own mailer.
• Encrypted secrets — provider passwords and API keys are encrypted at rest, and never returned by the REST API.
• No conflicts with core — mail is intercepted with the pre_wp_mail filter, so wp_mail() is never redeclared.

Source Code

The only compiled code in this plugin is the dashboard bundle in assets/admin/dist/ — one script and one stylesheet; nothing is obfuscated. Its full React and TypeScript source, with the Vite build configuration, is published in a public GitHub repository, tagged for each release.

To rebuild it (Node.js 20 or newer): cd assets/admin, then npm install and npm run build. The output filenames are fixed, so the build is reproducible and nothing is fetched at runtime.

Bundled Libraries

The scripts in assets/admin/dist/ are compiled from third-party npm packages — Mantine, TanStack Query, React Router, Recharts, Tabler Icons, Axios and Day.js among them — and none of them is fetched at runtime. React, ReactDOM and @wordpress/i18n are not bundled at all; the build maps them to the copies WordPress already ships. Every package is MIT licensed except a handful of indirect ones under ISC, BSD-3-Clause and 0BSD, all of which are compatible with this plugin’s “GPLv2 or later” license. assets/admin/package.json and assets/admin/package-lock.json in the repository linked above name and pin every package, direct and indirect.

No third-party PHP libraries are included.

External Services

Kelune SMTP stores all data in your own WordPress database. It connects to an external service only when you create and activate a connection for that service. No data is ever sent to the plugin author.

SMTP (your own mail server)
Used to deliver email when you create an SMTP connection. This is not a fixed third-party service: the plugin connects only to the mail server host you enter yourself.
– Data sent: message content, subject, recipient/sender addresses, headers and attachments, plus the SMTP credentials you configure.
– When sent: each time the plugin sends an email through this connection, and when you run a health check or send a test email.
– Service URL: the SMTP host you configure
– Terms / Privacy: governed by your own mail server provider

Amazon SES
Used to deliver email when you create an Amazon SES connection and enter AWS credentials. No request is made to Amazon until you have saved that connection.
– Data sent: the raw message — recipient/sender addresses, subject, content and attachments. The health check sends only your AWS credentials and no message data: it reads your account details (sending quota and status) from the /v2/email/account endpoint.
– When sent: each time the plugin sends an email through this connection, and when you run a health check or send a test email.
– Service URL: https://email.{your-region}.amazonaws.com/ — for example https://email.us-east-1.amazonaws.com/
– Terms of Service: https://aws.amazon.com/service-terms/
– Privacy Policy: https://aws.amazon.com/privacy/

Mailgun
Used to deliver email when you create a Mailgun connection and enter a Mailgun API key and sending domain.
– Data sent: message content, subject, recipient/sender addresses and attachments. The health check sends only your API key and sending domain, to confirm the domain exists on your account via the /v3/domains/{domain} endpoint.
– When sent: each time the plugin sends an email through this connection, and when you run a health check or send a test email.
– Service URL: https://api.mailgun.net (or https://api.eu.mailgun.net if you select the EU region)
– Terms of Service: https://www.mailgun.com/legal/terms/
– Privacy Policy: https://www.mailgun.com/legal/privacy-policy/

SendGrid
Used to deliver email when you create a SendGrid connection and enter a SendGrid API key.
– Data sent: message content, subject, recipient/sender addresses and attachments. The health check sends only your API key, to read the scopes granted to it from the /v3/scopes endpoint.
– When sent: each time the plugin sends an email through this connection, and when you run a health check or send a test email.
– Service URL: https://api.sendgrid.com
– Terms of Service: https://www.twilio.com/en-us/legal/tos
– Privacy Policy: https://www.twilio.com/en-us/legal/privacy