Senior React Developer (Java Backend)

Quick Facts

• Title: Senior React Developer (Java Backend)

• Work mode: Hybrid (3 days per week in Krakow office)

• Focus: Frontend development (React/TypeScript) with additional Java/Spring Boot backend contributions

Description

You will design and develop modern, scalable, responsive, high-performance web applications. The role is primarily frontend-focused (React, TypeScript, UI performance, state management, and REST API integration) with collaboration across UX/UI, product, and backend engineering. You will also contribute to Java backend development and RESTful microservice integration when needed.

Responsibilities

• Frontend (80%): build and maintain UI with React/TypeScript/JavaScript, create reusable modular components, implement responsive and accessible interfaces, manage state and data fetching, integrate with REST APIs, optimize rendering and browser compatibility, write clean testable code, and participate in code reviews.

• Automated testing: develop unit, integration, and end-to-end tests.

• Backend (20%): develop and enhance services using Java and Spring Boot, design and integrate RESTful APIs/microservices, define API contracts and data models, and support debugging/performance tuning across frontend and backend.

Requirements

• Commercial experience with React and TypeScript

• Strong JavaScript (ES6+), HTML5, and CSS3

• Experience with React Hooks and component/reuse patterns

• Practical state management experience (e.g., Redux Toolkit, Zustand, Context API)

• Experience integrating with RESTful APIs and handling async/API errors

• Knowledge of responsive design, accessibility, browser compatibility, and frontend performance optimization

• Working knowledge of Java and Spring Boot

• Understanding of REST/HTTP/JSON and backend API integration

• Familiarity with microservices architecture and service communication

Benefits

• Opportunity to work on complex business applications

• Contribute to architectural decisions and apply modern engineering practices in an Agile environment