Full-Stack Developer

For our client, we're looking for a Senior Fullstack Developer to join client team and contribute to its continued growth. Frontend (React): Build modern, responsive, and accessible UI components using React / Next.js; Implement clean, modular front-end architecture using hooks and component; libraries; Optimize rendering performance and frontend UX across devices; Collaborate with designers to turn UI/UX into functional interfaces. Backend (Node.js): Design and implement RESTful or GraphQL APIs using Node.js / Express / Nest.js; Build scalable microservices with proper separation of concerns; Work with relational and NoSQL databases (PostgreSQL, MongoDB, etc.); Implement authentication, authorization, and role-based access control; Integrate with third-party APIs and services (payments, notifications, etc.); Ensure robust error handling, logging, and testing. Requirements: 5+ years of experience in fullstack web development; Deep knowledge of JavaScript/TypeScript across both frontend and backend; Proficiency with React (or Next.js) and related frontend tooling (Webpack, Vite, etc.); Strong backend skills in Node.js and one or more frameworks (Express, Nest.js, etc.); Solid understanding of database design and query optimization (PostgreSQL, MySQL, MongoDB); Experience with API design, authentication flows, and JWT/OAuth2; Experience with Git, CI/CD, and automated testing; Strong architectural and problem-solving skills; Ability to communicate clearly, collaborate cross-functionally, and mentor others; Very good English language written and verbal communication skills. Nice to have: Experience with Cloud platforms (AWS, GCP, Azure); Experience with Docker, containerized deployments, or Kubernetes; Familiarity with serverless architecture (AWS Lambda, Firebase Functions); Exposure to microfrontend or monorepo setups (Turborepo, Nx); Familiarity with Agile processes, Jira, Scrum/Kanban boards. The offer:  Warsaw (Poland) - fully remote work (B2B contract); Vilnius (Lithuania) - hybrid/remote (B2B or employment contract). Rate: 5500 - 6100 EUR (negotible) Recruitment Process: CV Screening: Applications are reviewed within 24 hours. Pre-Screening Interview: A brief Q/A session ( Automated or with a Recruiter ) designed to learn more about your experience related to the required job position. Automated Session (Recommended) – You can complete this session on your own at a time that is convenient for you. The questions and follow-ups are well-structured and designed to highlight your experience and provide detailed insights into your background. This option is recommended because it's usually more detailed and allows us to provide feedback from the hiring manager faster. Session with a Recruiter – You can also have the session with a recruiter. The questions are the same, but the discussion may be a bit less detailed, and feedback might take a little longer. Shortlisting: Qualified candidates are presented to the hiring manager for review. Formal Interviews: On-site discussions with the hiring manager or project team, with feedback provided within 1-2 weeks. Offer and Onboarding: Successful candidates receive a formal offer and begin a structured onboarding process. Information about the processing of your personal data is provided in our Privacy Policy, which is available online at Privacy Policy  .