List of Ruby software and tools

Web tools

BioRuby – bioinformatics and computational biology library for Ruby
Bogus – Ruby library for creating reliable test doubles with contract verification
ERuby – embedded Ruby templating
EventMachine – event-driven I/O library
Factory Bot – test fixtures library
Fat comma – Ruby library for JSON-like hash syntax
Geocoder – Ruby library for geocoding and reverse geocoding addresses
Haml – HTML templating engine
Markaby – HTML generation via Ruby
Nokogiri – XML/HTML parsing library
RSpec – behavior-driven testing framework for Ruby
RubyGems – package manager for Ruby libraries and applications
Sass – CSS preprocessor
Sidekiq – background job framework for Ruby, used to handle asynchronous tasks.
Uconv – Unicode text conversion library
Watir – web application testing framework

HotRuby – Ruby interpreter implemented in JavaScript, enabling Ruby code to run in web browsers.
IronRuby – Ruby for .NET platform
JRuby – Ruby on the Java Virtual Machine
MacRuby – Ruby implementation for macOS
Mod ruby – Apache module that embeds the Ruby interpreter to improve performance of Ruby web applications
Mruby – lightweight Ruby interpreter
Rubinius – alternative Ruby implementation, based loosely on the Smalltalk-80 Blue Book design.
Ruby MRI – the standard Ruby interpreter
YARV – "Yet Another Ruby VM," the bytecode interpreter used in modern Ruby implementations