Senior C# Full Stack Engineer - AI Infrastructure

Software Engineer (C#) — Internal Tooling (AI Infrastructure) About The Role What if your C# skills could directly shape the infrastructure powering next-generation AI models? We're looking for a Senior C# Full-Stack Engineer to build and optimize the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on every day. This is a fully remote contract role working on real production systems — not toy projects or demos. You'll collaborate with research and engineering teams at the frontier of AI development, solving hard infrastructure problems that have genuine impact on how the world's most advanced models are built and evaluated. Organization: AlignerrType: Hourly ContractLocation: RemoteCommitment: 20–40 hours/week What You'll Do Design, build, and optimize high-performance C# systems supporting AI data pipelines and model evaluation workflowsDevelop full-stack tooling and backend services for large-scale data annotation, validation, and quality controlImprove reliability, performance, and safety across existing C# codebases used in production AI research environmentsCollaborate with data scientists, researchers, and engineers to support model training and evaluation infrastructureIdentify bottlenecks and edge cases in data and system behavior — then implement scalable, robust fixesParticipate in synchronous design reviews to iterate on architecture and implementation decisions Who You Are Native or fluent English speaker with clear written and verbal communication skillsFull-stack developer with a strong systems programming background3–5+ years of professional experience writing production-grade C#Experienced in interoperability scenarios — such as invoking Python ML models from .NET or wrapping native librariesSkilled at designing robust harnesses for benchmarking and evaluating system performanceAble to commit 20–40 hours per week with reliability and consistency Nice to Have Prior experience with data annotation, data quality, or evaluation systemsFamiliarity with AI/ML workflows, model training pipelines, or benchmarking frameworksExperience with distributed systems or developer tooling at scale Why Join Us Work directly with leading AI labs on cutting-edge production systems — not side projectsFully remote and flexible — structure your work around your lifeFreelance autonomy with the substance and scope of meaningful, high-impact engineering workGain deep exposure to AI infrastructure and evaluation workflows at the frontier of the fieldPotential for ongoing contract work and expanded scope as projects evolve