Ruby on Rails developers is responsible for designing, developing, and deploying web applications using the Ruby programming language. They have a wide range of skills, including:  -Strong knowledge of object-oriented design principles (OOP); -Proficiency in database management systems like PostgreSQL or MySQL;  -Ability to build efficient user interfaces with HTML/CSS and JavaScript libraries such as jQuery or ReactJS;   -Experience working with version control tools (Git);   -Understanding of system security best practices;       -Familiarity with server architecture concepts (Apache, Nginx);   -Knowledge of web services and APIs (RESTful & SOAP);      -Ability to write automated tests in RSpec or Cucumber.