Mailpit

Mailpit is a small, fast, low memory, zero-dependency, multi-platform email testing tool & API for developers.

It acts as an SMTP server, provides a modern web interface to view & test captured emails, and includes an API for automated integration testing.

• Runs entirely from a single static binary or multi-architecture Docker images
• Modern web UI with advanced mail search to view emails (formatted HTML, highlighted HTML source, text, headers, raw source, and MIME attachments including image thumbnails), including optional HTTPS & authentication
• SMTP server with optional STARTTLS or SSL/TLS, authentication (including an “accept any” mode)
• A REST API for integration testing
• Real-time web UI updates using web sockets for new mail & optional browser notifications when new mail is received
• Optional POP3 server to download captured message directly into your email client
• HTML check to test & score mail client compatibility with HTML emails
• Link check to test message links (HTML & text) & linked images
• Spam check to test message “spamminess” using a running SpamAssassin server
• Create screenshots of HTML messages via web UI
• Mobile and tablet HTML preview toggle in desktop mode
• Message tagging including manual tagging or automated tagging using filtering and “plus addressing”
• SMTP relaying (message release) - relay messages via a different SMTP server including an optional allowlist of accepted recipients
• SMTP forwarding - automatically forward messages via a different SMTP server to predefined email addresses
• Fast message storing & processing - ingesting 200-300 emails per second over SMTP depending on CPU, network speed & email size, easily handling tens of thousands of emails, with automatic email pruning by volume or message age (by default keeping the most recent 500 emails)
• Chaos feature to enable configurable SMTP errors to test application resilience
• List-Unsubscribe syntax validation
• Optional webhook for received messages

Installation Instructions

Linux

{
  "url": "{{ .SVar `.tool.mailpit.download.url` }}",
  "destination_folder": "{{ .PDownloads }}",
  "output_filename": "{{ .SVar `.tool.mailpit.download.filename` }}",
  "overwrite": false
}

{
  "destination": "{{ .PTools }}/mailpit/{{ .SVar `.tool.mailpit.download.version` }}",
  "max_file_size": 0,
  "skip_symlinks": false,
  "preserve_permissions": true,
  "remove_existing": true,
  "source": "{{ .PDownloads }}/{{ .SVar `.tool.mailpit.download.filename` }}"
}

MacOS

{
  "url": "{{ .SVar `.tool.mailpit.download.url` }}",
  "destination_folder": "{{ .PDownloads }}",
  "output_filename": "{{ .SVar `.tool.mailpit.download.filename` }}",
  "overwrite": false
}

{
  "destination": "{{ .PTools }}/mailpit/{{ .SVar `.tool.mailpit.download.version` }}",
  "max_file_size": 0,
  "skip_symlinks": false,
  "preserve_permissions": true,
  "remove_existing": true,
  "source": "{{ .PDownloads }}/{{ .SVar `.tool.mailpit.download.filename` }}"
}

Binaries

• mailpit