The official AWS X-Ray Recorder SDK for Ruby
Alba is a JSON serializer for Ruby
Ruby ODM framework for MongoDB
Ruby library for creating background jobs and processing them
A Ruby/Rack web server built for concurrency
Modern concurrency tools including agents, futures, promises, etc.
Guard is a command line tool to easily handle events on file system
Marathon supports testing of Java/Swing and Java/Fx applications.
Oga is an XML/HTML parser written in Ruby