Senior Backend Engineer (C#) - AI Data Platform

Senior Backend Engineer (C#) — AI Data PlatformAbout The RoleWhat if your C# engineering skills could directly shape the infrastructure powering the world's most advanced AI systems? We're looking for a Senior C# Engineer to design and build the data pipelines, annotation tooling, and evaluation infrastructure that leading AI labs depend on to train and improve next-generation models.This is a fully remote, flexible contract role working on real production systems at the frontier of AI development. If you're a seasoned backend engineer who wants meaningful, high-impact work — this is it.Organization: AlignerrType: Hourly ContractLocation: RemoteCommitment: 20–40 hours/weekWhat You'll DoDesign, build, and optimize high-performance C# systems supporting AI data pipelines and model evaluation workflowsDevelop backend services and tooling for large-scale data annotation, validation, and quality controlImprove reliability, performance, and safety across existing C# codebasesCollaborate with data, research, and engineering teams to support model training and evaluation infrastructureIdentify bottlenecks and edge cases in data and system behavior, then implement scalable, production-ready fixesParticipate in synchronous design reviews to iterate on architecture and implementation decisionsWho You AreNative or fluent English speaker with clear written and verbal communication skills5+ years of professional experience building scalable backend services in C#Strong systems programming background with full-stack development experienceDeep expertise in modern frameworks for RESTful APIs and RPC servicesExperienced integrating cloud-native data services and orchestrating workflows via message bus architecturesAble to commit 20–40 hours per week with reliability and consistencyNice to HavePrior experience with data annotation, data quality pipelines, or model evaluation systemsFamiliarity with AI/ML workflows, model training, or benchmarking infrastructureBackground in distributed systems design or developer toolingWhy Join UsWork directly on cutting-edge AI projects alongside the world's leading research labsFully remote and flexible — structure your hours around your lifeFreelance autonomy with the substance of high-impact, technically challenging workContribute to infrastructure that shapes the future of AI at a foundational levelPotential for ongoing engagement and expanded scope as new projects launch