Senior .NET Developer

Summary We are looking for a Senior .NET Developer to join a cross-functional agile team committed to building the core architecture and infrastructure of our next-generation platform. This is not just another feature team role. You will be contributing to the foundation of a scalable, cloud-ready system, designed to operate across Windows, Linux, and macOS environments. You'll work in a modern engineering ecosystem, using technologies such as .NET Core, Docker, Kubernetes, Kafka, Redis, and Ably, as well as evolving current .NET Framework solutions. Please note: This role follows a hybrid working model and requires onsite attendance at our Kraków/Warsaw office three days per week. What You'll DoDesigning and developing scalable microservices from the ground upImplementing according to architectural and product design documentsReverse engineering of current business logic modulesModernizing legacy components to meet new business requirementsWriting clean, maintainable code with a strong focus on quality and testability (TDD)Participating in code reviews and driving engineering guidelinesCollaborating closely with cross-functional teams across product, QA, and DevOpsBuilding and maintaining the team's AI tooling — reusable skills, custom agents, MCP servers, and repo instruction files that encode how our platform actually works What We're Looking For6+ years of experience in backend development using .NET / .NET CoreHands-on experience building large-scale web-based systemsSolid understanding of microservices architectureGood knowledge of relational databasesAnalytical mindset with strong problem-solving skillsAbility to work independently while being a reliable teammateContinuous learning approach and adaptability to new technologiesGood written and verbal English communication skills AI-first engineering (we mean this literally) Our codebase is too large to hold in your head, so we work with AI agents by default, and we invest in the tooling that makes them accurate here. We're looking for someone who:Uses agentic coding tools daily for real production work — not autocomplete, but delegating multi-step tasks and reviewing the output criticallyHas authored reusable agent tooling: skills, custom subagents, slash commands, MCP servers, hooks, or equivalent — and can talk about what made them work or failKnows how to give an agent the right context, scope a task so it succeeds, and recognize when the output is confidently wrongIs interested in improving our AI setup, not just consuming it If you've built something in this space — a skill, an agent, a tool, a workflow — mention it in your application. We'd rather see that than a certification. Nice to haveExperience with Docker and KubernetesFamiliarity with TDD and automated testing approachesUnderstanding of event-driven architecture (Kafka, pub/sub patterns) Compensation Philosophy We offer a comprehensive pay and benefits package designed to stay competitive in the market, support your wellbeing, and recognise your contribution to our success. Our approach is underpinned by a pay-for-performance belief in rewarding individual impact. Your specific compensation package will be determined by factors such as your skills, experience, qualifications, and location. Depending on your role and location, you may be eligible for annual bonuses and incentives, health and wellbeing benefits, paid time off, retirement plans, insurance coverage, and other local or statutory benefits. Specific details about compensation and benefits for this position will be discussed during the recruitment process.