Senior Backend Python Engineer

About Shelf Shelf builds software that helps enterprises make AI work in the real world. We care about the hard part: reliable systems, clear operational logic, and production-grade engineering that makes AI useful instead of brittle. Job Description: This role is for a senior backend engineer who can own important systems, not just implement tickets. You will take ambiguous problems, design the right backend approach, ship it, and keep it healthy in production. We want someone who is strong technically, communicates clearly, and has the judgment to make systems simpler, safer, and easier to evolve over time. This is a product engineering role with real ownership from system design through production. Location – Warsaw, work from the office. What You Will Own Design and ship backend services, APIs, data flows, and background processing for production systems. Turn vague requirements into concrete technical plans, trade-offs, and execution. Own services after launch: reliability, observability, performance, and incident follow-through. Make sound decisions around system boundaries, data models, interfaces, and scaling paths. Write clear technical specs, architecture notes, and diagrams when they help the team move faster. Work closely with product, frontend, and platform engineers to deliver end-to-end outcomes. Improve engineering leverage with AI tooling, automation, and internal workflows rather than using AI as a gimmick. Raise the quality bar through code review, design review, and pragmatic technical leadership. What Strong Performance Looks Like You reliably move important backend work forward without waiting to be tightly managed. Your systems are easier to operate and easier to change because of your design decisions. You communicate trade-offs clearly and make the team around you more effective. You use AI tools well: to accelerate analysis, implementation, debugging, writing, and repetitive work, while keeping a high verification bar. What We Are Looking For Strong senior-level backend engineering experience in production systems. Strong Python skills and the ability to design clean, maintainable backend code. Good distributed systems judgment: concurrency, failure handling, data consistency, async work, and service boundaries. Hands-on cloud experience in AWS, Azure, or a similar environment. Comfort with SQL and NoSQL systems, schema design, and performance tuning. Ability to go from problem statement to design to production rollout with real ownership. Clear written and verbal communication. You can explain systems, trade-offs, and incidents without hiding behind jargon. AI-native working style. You already use AI tools in your daily engineering workflow and want to keep pushing that further. Strong Plus Experience with LLM-backed systems, search, retrieval, AI infrastructure, or data-heavy pipelines. Working knowledge of TypeScript or the ability to contribute across the stack when needed. Experience shaping technical direction for other engineers, even without formal management responsibility. How We Evaluate Fit We care more about ownership, systems judgment, and learning velocity than a perfect keyword match to our stack. If you are the kind of engineer who can take a messy problem and turn it into a strong production system, we want to talk. What Shelf Offers: B2B contract. Company Stock Options. Hardware: MacBook Pro. Modern technical stack . Develop open-source software . GitHub Copilot subscription. Access to Claude Code, OpenAI Codex, TypingMind, and MCP Servers. Why Shelf: Our Leadership Team has deep knowledge management and AI domain expertise and enterprise SaaS background to execute this plan We love our customers and our customers love us. Ask a Shelf customer why, and they’ll tell you it’s because of our innovative capabilities, rock-solid reliability, they truly enjoy working with our people, but most of all – it’s the improvements they see in their business KPIs. We have raised over $60 million i