Ruby is a dynamic, reflective, object-oriented programming language. It was created by Yukihiro Matsumoto in Japan. Ruby was designed to be simple to learn and easy to use. It has a minimal syntax and relies on "gems" to add complexity to the language. Logging is a crucial part of any application. It helps to understand how the application is behaving, which allows us to take appropriate actions at the right time. Ruby Logging libraries are a set of libraries that help to write logs in the application. Ruby Logging is a standard for logging in Ruby. It's used by default in Rails and Sinatra, but can be used in any Ruby application. It provides functionality like colorized output, formatting of log messages and rotating files. Popular Ruby Logging open source libraries for developers include: logstash - Logstash transport and process your logs, events, or other data; fluentd - Fluentd: Unified Logging Layer; github-changelog-generator - Automatically generate change log.