Senior Backend Engineer

Senior Backend Engineer (C#) — AI Data Platform About The Role What if your C# expertise could directly shape the infrastructure powering the next generation of AI? We're looking for a Senior Backend Engineer to design and build the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and improve their most advanced models. This is a fully remote, flexible contract role for a seasoned engineer who thrives on solving hard systems problems and wants their work to matter at scale. Organization: AlignerrType: Hourly ContractLocation: RemoteCommitment: 20–40 hours/week What You'll Do Design, build, and optimize high-performance C# systems supporting large-scale AI data pipelines and evaluation workflowsDevelop backend services and tooling for data annotation, validation, and quality control at scaleImprove the reliability, performance, and safety of existing C# codebasesCollaborate with data, research, and engineering teams to accelerate model training and evaluationIdentify and resolve bottlenecks and edge cases across data and system behaviorParticipate in synchronous design reviews and iterate rapidly on architecture and implementation decisions Who You Are 5+ 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 with cloud-native data services and message bus architectures for workflow orchestrationNative or fluent English speaker with clear written and verbal communication skillsSelf-directed and reliable — able to commit 20–40 hours per week and deliver independently Nice to Have Prior experience with data annotation platforms, data quality pipelines, or evaluation systemsFamiliarity with AI/ML workflows, model training pipelines, or benchmarking infrastructureExperience with distributed systems design or developer toolingBackground working directly with or alongside AI research teams Why Join Us Work on real production systems used by leading AI research labs — not toy projectsFully remote and asynchronous-friendly — work from wherever you do your best workFlexible contract structure with meaningful, high-impact technical workCollaborate with top engineers and researchers pushing the boundaries of AIPotential for ongoing contract extensions as projects grow and new initiatives launch