Senior Fullstack Developer (AI Stack)

About us Lumen Dynamics is a specialist IT recruitment agency delivering top engineers across Poland and Europe 🇪🇺. We combine experienced recruiters with autonomous AI agents and an obsessive focus on quality — sourcing 24/7 across LinkedIn, GitHub, and beyond to reach engineers who aren't actively job hunting but are open to the right move. We don't flood you with CVs. We get to know each candidate's skills, values, and goals, then send only the best-matched people — and we stay close through onboarding and the first months to make sure the placement lasts. About the role You'll work on an AI-native platform for the legal industry — building agentic AI workflows that let legal teams delegate complex, multi-step work. Not just chat-based assistance, but actual end-to-end execution on documents: review, drafting, analysis, anonymization, translation, and semantic search. The product is highly scalable and performant, handling large volumes of large legal documents. You'll work very closely with the product, with real ownership and impact on its direction. We're looking for top-tier engineers who deliver high-quality code and challenge decisions rather than just execute tickets. Tech stack Python, FastAPI, Redis, SQL, NoSQL, Celery, Azure Cloud, React, Next.js, TypeScript, shadcn/ui, Zustand Must-have Strong English communication (C1+) Experience building scalable, robust backend systems within (or close to) the stack above Hands-on experience with AI tooling in your daily work (Claude Code, Cursor, etc.) — this is a hard requirement Comfort in a fast-paced, international startup environment Nice to have Experience building LLM-powered features or workflows (OpenAI/Anthropic APIs, LangChain, agentic systems)