C# Infrastructure Engineer - Data Pipelines

Seattle

**C# Infrastructure Engineer --- Data Pipelines (AI Training)** **About The Role** What if your C# skills could directly shape the infrastructure powering next-generation AI systems used by millions of people? We're looking for a Senior C# Full-Stack Engineer to design and build the high-performance data pipelines, annotation tooling, and evaluation systems that sit at the heart of cutting-edge AI development. This is a fully remote, flexible contract role working alongside leading AI labs on real production systems and high-impact engineering challenges. If you're a senior engineer who thrives on performance, scalability, and building things that actually matter --- this is the role for you. * Organization: Alignerr * Type: Hourly Contract * Location: Remote * Commitment: 20--40 hours/week **What You'll Do** * 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 resilience 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 architecture and implementation decisions **Who You Are** * Native or fluent English speaker with strong written and verbal communication skills * Full-stack developer with a deep systems programming background * 5+ years of professional experience writing production-grade C# * Proven experience building streaming data pipelines using asynchronous streams and reactive programming patterns * Skilled at optimizing I/O-bound operations and implementing resilient retry and fault-tolerance strategies for distributed data ingestion * Able to commit 20--40 hours per week with reliability and consistency **Nice to Have** * Prior experience with data annotation, data quality pipelines, or model evaluation systems * Familiarity with AI/ML workflows, model training, or benchmarking infrastructure * Experience with distributed systems architecture or developer tooling **Why Join Us** * Work on cutting-edge AI projects alongside leading research labs * Fully remote and flexible --- work when and where it suits you * Freelance autonomy with the structure and impact of meaningful, production-level work * Make a direct, tangible contribution to the infrastructure powering next-generation AI * Potential for ongoing work and contract extension as new projects launch