Fullstack Java & React Developer – Kraków (Hybrid)

We are looking for a highly skilled Fullstack Developer with expertise in Java and React.js to join our Kraków-based development team. You will design, develop, and maintain scalable, high-performance web applications, contributing to both backend services and rich frontend interfaces. This role follows a hybrid working model, with 2–3 days per week onsite in Kraków. Key Responsibilities • Backend Development: Architect, implement, and maintain backend services using Java, Spring Boot, and related frameworks • Frontend Development: Build responsive, modular, and maintainable React.js applications with a focus on component-driven design • Design and implement RESTful APIs and microservices, ensuring high performance, security, and scalability • Collaborate with cross-functional teams to define technical requirements, system architecture, and feature implementation • Apply unit testing, integration testing, and end-to-end testing best practices (JUnit, Mockito, Jest, React Testing Library) • Participate in code reviews, enforce coding standards, and promote best practices in clean code, SOLID principles, and design patterns • Troubleshoot and optimize application performance and resolve production issues • Manage CI/CD pipelines, automate deployments, and support DevOps practices • Stay up-to-date with emerging technologies and frameworks to continuously improve application architecture Required Skills and Experience • Strong experience with Java, Spring Boot, and related backend frameworks • Solid experience with React.js, Redux, or state management libraries • Proven experience in designing and consuming RESTful APIs and microservices architecture • Proficient in JavaScript, HTML5, CSS3, and modern frontend tooling (Webpack, Babel, ESLint) • Experience with relational databases (MySQL, PostgreSQL) and/or NoSQL databases • Familiarity with Git, version control workflows, and Agile/Scrum methodologies • Understanding of unit testing, integration testing, and test-driven development (TDD) • Good problem-solving and communication skills in English Nice to Have • Experience with TypeScript and advanced React patterns (Hooks, Context API, Suspense) • Knowledge of Docker, Kubernetes, or cloud platforms (AWS, Azure, GCP) • Experience with event-driven architectures, message queues, or Kafka • Familiarity with GraphQL or WebSocket-based real-time applications