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Senior Backend Engineer (C#) - AI Data Platform

$50-75/hrRemoteFreelanceCODING

About the Role

What 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: 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 model evaluation workflows
  • Develop backend services and tooling 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 infrastructure
  • Identify bottlenecks and edge cases in data and system behavior, then 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 clear written and verbal communication skills
  • 5+ years of professional experience building scalable backend services in C#
  • Strong systems programming background with full-stack development experience
  • Deep expertise in modern frameworks for RESTful APIs and RPC services
  • Experienced integrating cloud-native data services and orchestrating workflows via message bus architectures
  • 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
  • Background in distributed systems design or developer tooling

Why Join Us

  • Work directly on cutting-edge AI projects alongside the world's leading research labs
  • Fully remote and flexible — structure your hours around your life
  • Freelance autonomy with the substance of high-impact, technically challenging work
  • Contribute to infrastructure that shapes the future of AI at a foundational level
  • Potential for ongoing engagement and expanded scope as new projects launch