Tsimafei Yefimenka

Senior Full-Stack Engineer — React, Next.js, Node.js, TypeScript

Senior full-stack engineer with 8 years building scalable web platforms on React, Node.js and TypeScript, about five of them with UK and EU clients. Leads feature delivery, mentors engineers and pushes on performance across FinTech, EdTech and B2B SaaS. Lately works spec-first with AI-assisted tooling and evaluates LLM output for AI labs.

Open to senior roles: remote within Poland, or hybrid in Łódź or Warsaw — he is considering a move to Warsaw. Works on B2B through his own sole proprietorship or on a permanent contract (umowa o pracę). Notice period is two weeks. Can align hours with US Eastern time, with heavy overlap during the first months of onboarding. Prefers established companies with a healthy engineering culture.