Mailpit - Email & SMTP Testing Server

This is a repackaged open source software product wherein additional charges apply for cloudimg support services.

Overview

Mailpit is a self-hosted email and SMTP testing tool for developers. It runs a fake SMTP server that catches the mail your applications send, then shows every captured message in a fast, searchable web interface - rendered HTML, plain text and raw source, attachments, headers, and spam and link checks. Because Mailpit never delivers mail to real recipients, you can safely point a development or staging environment at it and inspect exactly what your app would have sent. This image delivers Mailpit fully installed and running behind an nginx reverse proxy, so a mail-testing console is serving within minutes of launch. The current release available is Mailpit 1.30.3.

Application Stack

Mailpit is a single static Go binary that runs as a dedicated system user under systemd. It listens for SMTP on port 25 and serves its web UI and REST API on the loopback interface, fronted by nginx on port 80 with the WebSocket upgrade its live-updating message list needs already configured. Every captured message is stored in a SQLite database on a dedicated data disk so it is independently resizable and separate from the operating system disk.

Catch And Inspect Every Message

Point your application's SMTP settings at this instance on port 25 and Mailpit captures everything it sends. The web UI lists messages as they arrive in real time and lets you view the rendered HTML, the plain-text part and the raw source, download attachments, inspect every header, and run spam-score and link checks. Search across captured mail, follow message threads, and use the HTML check to see how a message renders across email clients. A full REST API exposes the same message store for automated tests.

Secure First Boot

On the first boot of your instance a one-shot service generates a UI password unique to that instance, applies it to Mailpit as an htpasswd bcrypt credential, and records it in a file only the root user can read. No shared or default credentials ship in the image, and the health endpoints used by load balancers stay open while the UI and API require the generated password.

Ready To Use

Open the web UI in your browser, read the generated password, sign in, and send a test message to port 25 to see it appear instantly. A built-in health endpoint answers on the reverse proxy for load-balancer and uptime checks. The message database lives on a dedicated, independently resizable data disk.

cloudimg Support

24/7 technical support by email and chat. Help with deployment, HTTPS and reverse-proxy configuration, SMTP relay and integration, storage and upgrade planning.

Use Cases

Inspect the mail your application sends from development and staging without risk of it reaching real recipients. Debug transactional email templates, HTML rendering and attachments. Give QA and support teams a shared inbox to verify sign-up, password-reset and notification flows. Wire the REST API into automated integration tests that assert a message was sent.

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