2+ years of industry experience developing and maintaining commercial Ruby applications. 12+ months of demonstrated commercial experience with React.js. Strong practical understanding of Object-Oriented Programming (OOP), SOLID principles, and backend system design. Ability to work independently on standard engineering tasks. Experience with Sidekiq or similar background processing tools. Ability to build new UI components in React.js. Familiarity with RESTful APIs. Excellent verbal and written communication skills in both Polish and English.