luhnacy can be used to validate strings for Luhn compliance as well as generating valid or invalid strings for the purposes of testing

Efficient Luhn checksum validator

Ruby library for the WHM & cPanel API; It's not a half day or anything like that

The new de-facto for API testing your Rails application

I am Magi.

Simple, pure-ruby library for making pretty Wordle-like clouds. It uses RMagick as graphic backend.

MagicLamp provides an easy way to get your Rails templates into your JavaScript specs.

A ruby library for reading and writing arbitrary messages in DJB's maildir format

GPG/MIME encryption plugin for the Ruby Mail Library This tiny gem adds GPG capabilities to Mail::Message and ActionMailer::Base. Because privacy matters.

Manage the mails you send from Rails.

ManageIQ SmartState Analysis

downloads any manga from MangaReader.net

Integrate MapBox.js with the Rails asset pipeline

Easily sync your certificates and profiles across your team using git

Material Design Lite, for Rails

matplotlib wrapper for Ruby

Mayu Live is a live updating server side VirtualDOM framework for Ruby, inspired by modern frontend tools that exist in the JavaScript ecosystem.

A Ruby wrapper for the Ambassador API

Simple editor for markdown and rails

Ruby client for memcached supporting advanced protocol features and pluggable architecture.