Senior Full Stack Product Engineer

About Shelf Shelf builds software that helps enterprises make AI work in the real world. We build products people depend on, which means product judgment, engineering quality, and execution speed all matter at the same time. About the Role This role is for a senior full stack engineer with strong product instincts. You will own meaningful product slices end to end: understand the problem, shape the approach, build the frontend and backend pieces, ship them, and improve them based on real usage. We want someone who is equally comfortable improving a user flow, shaping an API, and closing the loop on quality in production. This is a product engineering role with real end-to-end ownership. Location – Warsaw, work from the office. What You Will Own Build and ship user-facing product features across frontend and backend boundaries. Turn rough product goals into practical solutions with good scope, sensible trade-offs, and strong execution. Work comfortably in UI, application logic, APIs, and data flows rather than stopping at team boundaries. Partner closely with product and design while still being able to move when the spec is incomplete. Improve usability, clarity, performance, and reliability, not just feature completeness. Instrument what you ship so we can learn from production behavior and iterate quickly. Use AI tools daily to move faster and help improve internal workflows, tooling, and engineering leverage. Keep the bar high on code quality, testing, and ownership after launch. What Strong Performance Looks Like You can take a vague product problem and turn it into a shipped, well-reasoned solution. Your features feel coherent end-to-end because you care about both implementation and product quality. You do not treat frontend and backend as separate worlds; you use both to solve the actual problem. You bring momentum. Work moves because you are on it. What We Are Looking For Strong senior-level experience shipping production web products. Strong frontend ability with React and TypeScript or an equivalent modern web stack. Real backend ability. You do not need to be backend-only, but you can design and ship APIs, backend logic, and data flows when the product needs it. Strong product sense. You notice awkward flows, weak defaults, and unnecessary complexity, and you improve them. Good judgment about scope, iteration, and technical trade-offs. Clear communication and comfort working across engineering, product, and design. AI-native working style. You already use AI tools as part of daily implementation and problem solving, and you are excited to improve how engineering work gets done. Strong Plus Experience with AI-powered product experiences such as chat, search, recommendations, workflows, or agent-like systems. Experience with Python, Node.js, or both on the backend. Experience owning product areas with limited oversight. Strong feel for performance, accessibility, and production quality in complex web applications. How We Evaluate Fit We care more about end-to-end ownership, product sense, and the ability to ship meaningful work than a perfect match to every framework on paper. If you are the kind of engineer who can make a product better from multiple angles, we want to talk. What Shelf Offers B2B contract. Stock options. MacBook Pro. A strong AI-native engineering environment with modern tools and room to experiment. Our Values: Quality - We’re united by our focus on world‑class Quality. Quality in all things – starting with everything that leaves your desk. Everything you touch – every email, report, campaign, and piece of code – should be outstanding. Your work product should blow people away. Having people look at what you’ve done and say, “Wow.” That’s the standard here. Remember that how you do anything is how you do everything. Focus on craftsmanship—your ability to make things better. Momentum - for us means that you should know that the things you’re responsible for are moving forward. When you look around an