Full-Stack Developer (RoR/React)

Stack

Responsibilities

• ▹Understand the existing Rails application and its production workflows
• ▹Modernize Rails incrementally into a clean API-first backend, no big-bang rewrite
• ▹Build new React web features and APIs reusable by the React Native/Expo app
• ▹Remove or replace legacy code and upgrade outdated dependencies safely
• ▹Work with PostgreSQL, Sidekiq/Redis, Stripe, AWS, and Elastic Beanstalk
• ▹Add tests, review AI-generated code, and ship small, reliable releases

Requirements

• ▹5+ years of software engineering experience with strong Ruby on Rails and React skills
• ▹Production experience modernizing or upgrading a legacy Rails application
• ▹Strong REST API, PostgreSQL, background jobs, authentication, and authorization knowledge
• ▹Experience with Stripe, AWS, automated testing, CI/CD, and production debugging
• ▹Able to work independently with a technical lead and communicate clearly in English

Nice to have

• ▹React Native/Expo experience
• ▹Rails/Ruby upgrade and migration experience from ERB, jQuery, or Webpack to React
• ▹Experience with user-generated media, video, fundraising, or K-12 products
• ▹Practical use of Claude Code, Cursor, Copilot, Codex, or similar tools

Soft skills

What we offer

• ▹Fixed benefit health care coverage
• ▹50% coverage for sports activities up to a fixed amount
• ▹Celebrating significant life events (birthday, wedding, birth of a child)
• ▹Support for professional and personal development
• ▹Flexible work, from anywhere, flexible hours within the project's working hours
• ▹Referral bonus for referring open positions
• ▹Regular online and offline company events

About the company

Kernelics is an international company with development centers in Poland and Georgia, gathering IT specialists and building teams for startups worldwide.