About the role Commit builds software products for clients across embedded, IoT, SaaS, AI/ML, e-commerce, mobile, and web. We’re looking for a Senior .NET Backend Engineer to join a strong, high-bar team building high-performance, secure .NET services. You’ll be a hands-on contributor — designing and writing production backend code, shaping technical decisions alongside your teammates, and delivering for clients (including large enterprise and banking environments). What you’ll do • Design and build robust, high-performance, secure backend services in C# / .NET. • Contribute to backend architecture and technical decisions alongside the team. • Design and document APIs (Swagger / OpenAPI) for clean, well-versioned integrations. • Take part in code reviews and help uphold the team’s engineering standards. • Drive performance, reliability, and secure-by-design practices in your code. • Contribute to build, packaging, and deployment so releases are repeatable and reliable. Must-have qualifications • 5+ years in backend engineering. • 1+ years experience in AI Tools Claude Code, Copilot, Cursor • Expert-level command of the core .NET stack: C#, .NET / .NET Core, ASP.NET Core, Entity Framework, LINQ, and async/concurrent programming. • Strong networking fundamentals (TCP/IP, HTTP/S, sockets) and API/service communication. • Proven performance-engineering skills: profiling, optimization, and advanced debugging of complex systems. • Strong background in secure code writing (OWASP, secure SDLC, common vulnerability classes and mitigations). • Experience with API design and documentation using Swagger / OpenAPI (e.g. Swashbuckle). • Software packaging and deployment experience (NuGet, containers/Docker, CI-driven artifacts, installers). • Fluent with modern dev tooling: Git, JIRA, Jenkins. • Professional-level English. • Excellent interpersonal and communication skills. Nice to have • Cloud experience (Azure / AWS) and microservices or messaging (e.g. gRPC, RabbitMQ, Kafka). • Experience with AI-first development (Claude Code, Cursor). • Additional programming languages and frameworks. • Experience working in large organizations (e.g. banking / financial services).