FullStack Consultant (TypeScript, React, and Next.js)

Type of contract: B2B contract Salary range: 90 - 125 PLN/H What will you do? You will build and improve user-facing experiences and product APIs that support modern data services. The role combines strong frontend development with practical full-stack delivery, translating product needs into accessible, reliable, and secure solutions across browser and service layers. Your tasks Design, build, and maintain TypeScript and Next.js user interfaces that are responsive, accessible, and aligned with business needs Deliver end-to-end product features across frontend and backend integration layers Collaborate with product, UX, backend, and data teams to refine user journeys, data contracts, and acceptance criteria Build secure and maintainable frontend solutions using reusable components and well-structured state management Integrate frontend applications with Java 21 and Spring Boot services Diagnose and resolve UI defects, API integration issues, performance bottlenecks, and production issues Develop and maintain unit, integration, and regression tests Support application quality through observability, logging, performance tuning, and production follow-up Maintain high engineering standards for code quality, code reviews, secure development, and deployment readiness Requirements Strong experience with TypeScript, React, and Next.js Good understanding of modern frontend architecture, component design, state management, routing, API integration, and accessible UI patterns Experience delivering full-stack features across browser and service layers Working knowledge of Java and modern Spring Boot application patterns Experience with REST APIs, DTOs, authentication flows, and integration contracts Ability to write clean and maintainable code and participate in technical design and code reviews Understanding of secure frontend and backend practices, including token handling, role-based access, and safe data handling Strong problem-solving skills and experience investigating production issues across UI and API layers Good communication and collaboration skills Openness to work hybrid from our client's office (Kraków) 6 days a month Nice to have React Query, Redux Toolkit, TanStack Query, or similar state management and data-fetching solutions Axios, forms, validation, and component libraries Spring Web, Spring Security, or Spring Data JPA PostgreSQL, database design, or database migration patterns OpenTelemetry, Micrometer, structured logging, or production monitoring tools Cloud-native or containerised delivery environments JUnit 5, Vitest, Playwright, or equivalent testing frameworks