Mailpit - email testing for developers

Mailpit is a multi-platform email testing tool & API for developers.

It acts as both an SMTP server, and provides a web interface to view all captured emails.

Mailpit is inspired by MailHog, but much, much faster.

Features

• Runs entirely from a single binary, no installation required
• SMTP server (default 0.0.0.0:1025)
• Web UI to view emails (formatted HTML, highlighted HTML source, text, headers, raw source and MIME attachments including image thumbnails)
• Mobile and tablet HTML preview toggle in desktop mode
• Advanced mail search (see wiki)
• Message tagging (see wiki)
• Real-time web UI updates using web sockets for new mail
• Optional browser notifications for new mail (HTTPS only)
• Configurable automatic email pruning (default keeps the most recent 500 emails)
• Email storage either in a temporary or persistent database (see wiki)
• Fast SMTP processing & storing - approximately 70-100 emails per second depending on CPU, network speed & email size, easily handling tens of thousands of emails
• SMTP relaying / message release - relay messages via a different SMTP server (see wiki)
• Optional SMTP with STARTTLS & SMTP authentication, including an "accept anything" mode (see wiki)
• Optional HTTPS for web UI (see wiki)
• Optional basic authentication for web UI (see wiki)
• A simple REST API (see docs)
• Multi-architecture Docker images

Installation

The Mailpit web UI listens by default on http://0.0.0.0:8025, and the SMTP port on 0.0.0.0:1025.

Mailpit runs as a single binary and can be installed in different ways:

Install via Brew (Mac)

Add the repository to your taps with brew tap axllent/apps, and then install Mailpit with brew install mailpit.

Install via bash script (Linux & Mac)

Linux & Mac users can install it directly to /usr/local/bin/mailpit with:

sudo bash < <(curl -sL https://raw.githubusercontent.com/axllent/mailpit/develop/install.sh)

Download static binary (Windows, Linux and Mac)

Static binaries can always be found on the releases. The mailpit binary can extracted and copied to your $PATH, or simply run as ./mailpit.

Docker

See Docker instructions.

Compile from source

To build Mailpit from source see building from source.

Configuring sendmail

There are several different options available:

You can use mailpit sendmail as your sendmail configuration in php.ini:

sendmail_path = /usr/local/bin/mailpit sendmail

If Mailpit is found on the same host as sendmail, you can symlink the Mailpit binary to sendmail, eg: ln -s /usr/local/bin/mailpit /usr/sbin/sendmail (only if Mailpit is running on default 1025 port).

You can use your default system sendmail binary to route directly to port 1025 (configurable) by calling /usr/sbin/sendmail -S localhost:1025.

You can build a Mailpit-specific sendmail binary from source (see building from source).

Why rewrite MailHog?

I had been using MailHog for a few years to intercept and test emails generated from several projects. MailHog has a number of performance issues, many of the frontend and Go modules are horribly out of date, and it is not actively developed.

Initially I tried to upgrade a fork of MailHog (both the UI as well as the HTTP server & API), but soon discovered that it is (with all due respect to its authors) poorly designed. It is in my opinion over-engineered (split over 9 separate projects), and performs very poorly when dealing with large amounts of emails or processing emails with an attachments (a single email with a 3MB attachment can take over a minute to ingest). Finally, the API transmits a lot of duplicate and unnecessary data on every browser request, and there is no HTTP compression.

In order to improve it I felt it needed to be completely rewritten, and so Mailpit was born.