Senior Backend Engineer (C#) - AI Data Platform

About The JobAlignerr connects top technical experts with leading AI labs to build, evaluate, and improve next-generation models. We work on real production systems and high-impact research workflows across data, tooling, and infrastructure.PositionSenior C# Full-Stack Engineer — AI Data & InfrastructureType: Contract, Remote Commitment: 20–40 hours/week Compensation: Competitive, hourly (based on experience)Role Responsibilities Design, build, and optimize high-performance systems in C# 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 fixes Participate in synchronous reviews to iterate on system design and implementation decisionsQualificationsMust-Have Native or fluent English speaker Full-stack developer experience with a strong systems programming background 5+ years of professional experience building scalable backend services in C#. Mastery of modern frameworks for building RESTful APIs and RPC services for inter-service communication. Experience integrating with cloud-native data services and orchestrating workflows via message bus architectures. Clear written and verbal communication skills. Ability to commit 20–40 hours per week.Preferred Prior experience with data annotation, data quality, or evaluation systems Familiarity with AI/ML workflows, model training, or benchmarking pipelines Experience with distributed systems or developer toolingApplication Process Submit your resume Complete a short technical screening Project matching and onboarding