Skip to content
CAI
Produce a survey ↗Verify a survey

sj26/mailcatcher

MailCatcher is a local mail testing tool that intercepts and stores incoming SMTP messages in an in-memory SQLite database. It provides a web-based interface, built with Sinatra and ERB templates, to view, search, and manage caught emails. The system also includes a CLI utility for forwarding mail and supports various email formats and encodings for testing purposes.

53.0

Adequate · 2 August 2026

634

lines of production code

Ruby

primary language

1

bus factor · 57 authors in all

3

measurements over time

CAI band scale
CAI trend line

How it got here

2010 · Architecture modernization and dependency updates

This period focused on modernizing the MailCatcher codebase by refactoring the library into a modular structure and migrating the web interface from Haml to ERB templates. Concurrently, the project updated its Ruby and gem dependencies, while introducing in-memory message storage and improved SMTP handling.

5 changes

2011–2021 · Web interface and frontend modernization

This period focused on modernizing the Mailcatcher web interface by migrating to Sinatra and Sprockets, while introducing CoffeeScript and various JavaScript libraries for enhanced functionality. The team also established a comprehensive RSpec test suite to ensure the reliability of these new features and the core application logic.

7 changes

CAI lens gauges

Survey your own repository

sj26/mailcatcher was measured the same way every project in this corpus was: the same rubric, at a pinned commit, with the result published in full. Point the surveyor at a repository you know and see whether you agree with it.

Survey a repository

About this page

  • The description of this project is derived from its own commit history, not from its README.
  • The score is its highest published measurement, taken on 2 August 2026 at a pinned commit. It is not a live figure and does not change until the project is measured again.
  • Measured at commit fbe811a53a — the exact code this score is about.
  • Scored under rubric rubric-2026.08.18. Score the same commit under that rubric and you get the same number.
CAI link cards