Software Engineer

Upside is an applied AI engineering and consultancy firm. We build software for scaling companies, international brands and large institutions. Our team design, build and run systems, with particular depth in healthcare and life sciences. Alongside client delivery, we develop our own IP: frameworks and components distilled from systems we've taken to production. Clients come to us when the problem is unclear and the stakes are high. Our job is to work out what should actually be built, build it properly, and leave behind a system the client can own. The role At Upside, a modern software engineer brings three disciplines together: Engineer - owning the technical decisions that make a system hold up in production: architecture, data, security, performance and failure modes. Consultant - learning the client's domain in depth: their processes, data, and regulatory and operational constraints. Then turning that understanding into technical decisions. Product thinker - thinking about how a system behaves at scale, how it fails and how it's operated after launch, and you scope deliberately so that only what creates value gets built. Responsibilities: Work directly alongside client engineering and product teams on business requirements, architect solutions, and own delivery all the way through to production. Drive complex system development with coding agents as your core delivery engine, manage context, decompose architectural specs into agent-executable tasks, and run work in parallel under strict quality control. Review generated implementations critically, design the tests, evals, and runtime checks that catch edge cases and silent failures, and hold a high bar on security, performance, and maintainability. Make the foundational design calls on data models, integration boundaries, security parameters, and trade-offs, and document them for both human and synthetic contributors. Share proven workflows, evaluation methods, and agent orchestration patterns so the whole engineering team levels up, and contribute to Upside’s open-source frameworks Proven background as a Software Engineer - you’ve built, architected, and owned complex backend/cloud systems end-to-end. Production experience with LLM coding agents - you’ve applied them to production-grade software engineering, not only experiments. Hands-on experience shipping LLM-powered features - you’ve built, shipped, or integrated LLM-powered and agentic components into production software systems. Comfort with shifting ground and full ownership - you stay effective when requirements, tools, and domain contexts change, and you take responsibility for the technical outcome from initial problem discovery to post-launch stability. Strong client-facing communication - you work directly with client tech leaders, challenge assumptions constructively, and explain complex architectural trade-offs clearly to both technical and non-technical stakeholders. Strong Python skills - or you bring deep experience in another major backend language like Ruby, Java, TypeScript, or Rust, and you’re ready to pivot to Python quickly. Fluent English (C1+) - you’ll collaborate directly with international clients. A university degree in Computer Science, Software Engineering, or a related technical field - highly valued. Nice to Have Fullstack Experience: Frontend experience with React or Vue; cloud and infrastructure work (AWS, Docker, Kubernetes). Open Source: History of contributions to open-source tools or libraries. How we work Built for the Long Run: We hire for the company, not a temporary project. We look for engineers who want to grow with Upside over time. Small, Accountable Teams: 3-9 people per project. We're small by design, meaning your technical decisions carry weight and your impact is visible. Mission-Critical Work: We tackle complex technical challenges that move the needle for international brands, scaling companies, and large institutions under real load. Real Autonomy: Complete freedom to drive solutions, experiment with novel agentic workflows, and lead implementations without unnecessary oversight. Uncapped Tooling: Your stack is fully covered (Claude Code, OpenAI Codex, and any tool that increases your velocity or sharpness). Location Kraków first, hybrid or remote from anywhere in Poland. If you'd like to understand more about how we work or read about the recruitment process in detail, feel free to explore our handbook . If something important to you isn't mentioned, share your thoughts with us at careers@upsidelab.io .