.NET Developer

Description Halcyon Labs is a trusted partner in digital commerce. The company helps leading brands modernize B2B solutions, marketplaces, and retail ecosystems. Since 2008, it has empowered businesses with cutting-edge technology, AI-powered personalization, and world-class engineering and design teams. A certified B Corporation®, Halcyon Labs is trusted by major brands including IKEA, VW, OLX, Delivery Hero, Żabka, Wolt, Careem, and Vinted. How freelancing works at Halcyon Labs? As a , you can choose what works well for you. You decide when, where, and how you work on projects and tasks. We match you with work that fits your skills. Plus, you have access to various opportunities across different industries and companies. That means you will not only gain more experience, but also develop various skills. But there's more. Halcyon Labs freelancers can benefit from full-time collaboration and really be a part of the team. So, are you ready to make an impact? Join Halcyon Labs, and let's build beautiful software together. We are looking for a Senior .Net Developer - AI Native with React Freelance assignment : full-time, B2B contract. Start: mid July Duration: 3 months with the possibility of extension Working hours: CET Location: Remote (based in European Union) Polish language is a must-have Requirements Strong proficiency in C# and .NET 8+. Experience building RESTful APIs with ASP.NET Core. Solid knowledge of React and TypeScript. Experience with SQL databases (SQL Server/PostgreSQL). Understanding of Clean Architecture , design patterns, and testing practices. Hands-on experience integrating LLMs (OpenAI, Claude, Gemini) into applications. Experience with AI frameworks (e.g. Semantic Kernel , LangChain or similar). Proficiency with Git , Docker , and CI/CD pipelines. Experience working with Google Cloud Platform and/or other cloud platforms. Strong problem-solving skills and ability to work independently. Good communication skills and experience collaborating in cross-functional teams. Polish and English at C1 level. Benefits In return, we offer: Flexibility: 100% remote work. Professionality: dev-friendly processes, like Continuous Integration and Code Review, work in line with Agile methodology. Diversity: projects from various industries like fintech, healthcare, insurance, or education. Growth: work with a team of experts and continuous development of your hard and soft skills. Knowledge: knowledge sharing sessions, internal knowledge base. Curious to learn more about working as a Halcyon Labs freelancer? All the information you need is here: . Looking for a full-time job? Check out our and find out more about our open recruitment processes. If you need any disability-related adaptation at any step of the recruitment process – simply let the recruiter know! We'd be happy to help. Don't hesitate and apply right away.