Senior C# Full-Stack Engineer: AI Data & Infrastructure

* Design, build, and optimize high-performance C# systems supporting AI data pipelines and evaluation workflows * Develop full-stack tooling and backend services for large-scale data annotation, validation, and quality control * Improve reliability, performance, and safety across existing C# codebases * Collaborate with data, research, and engineering teams to support model training and evaluation workflows * Identify bottlenecks and edge cases in data and system behavior, and implement scalable, production-ready fixes * Participate in synchronous design reviews to iterate on system architecture and implementation decisions

Who You Are

* Full-stack developer with a strong systems programming background and deep C# expertise * 3–5+ years of professional experience writing production C# code with a focus on modern standards * Solid understanding of performance optimization, concurrency (threading, atomics), and memory safety * Clear and precise written and verbal communicator — you can articulate technical decisions confidently * Native or fluent English speaker * Available to commit 20–40 hours per week consistently

Nice to Have

* Prior experience with data annotation, data quality, or evaluation systems * Familiarity with AI/ML workflows, model training pipelines, or benchmarking systems * Experience with distributed systems or developer tooling * Background working with or alongside research teams in fast-moving technical environments

Why Join Us

* Work directly on cutting-edge AI systems used by leading research labs * Fully remote and flexible — structure your work around your life * Freelance autonomy with the depth and impact of high-stakes engineering work * Collaborate with world-class engineers and researchers on problems that actually matter * Potential for ongoing work and contract extension as projects evolve and expand