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Senior C# Full-Stack Engineer — AI Data & Infrastructure

$50-75/hrRemoteFreelanceCODING

About the Role

What if your C# expertise could directly shape the infrastructure powering the next generation of 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 to train and improve their most advanced models.

This is a fully remote contract role with meaningful technical challenges, flexible hours, and the chance to work at the frontier of AI development — without leaving your home office.

  • 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 evaluation workflows
  • Develop full-stack tooling and backend services for large-scale data annotation, validation, and quality control
  • Improve reliability, performance, and safety across production 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, production-ready fixes
  • Participate in synchronous design reviews to iterate on architecture and implementation decisions

Who You Are

  • Native or fluent English speaker with strong written and verbal communication skills
  • Experienced full-stack developer with a solid systems programming foundation
  • 3–5+ years of professional experience writing production C# (modern standards preferred)
  • Deep understanding of performance optimization, concurrency (threading, atomics), and memory safety
  • Methodical problem-solver who thrives in fast-moving, high-stakes technical environments
  • Able to commit 20–40 hours per week with reliability and professionalism

Nice to Have

  • Prior experience with data annotation, data quality pipelines, or evaluation systems
  • Familiarity with AI/ML workflows, model training, or benchmarking infrastructure
  • Experience with distributed systems or internal developer tooling
  • Background working alongside research or data science teams

Why Join Us

  • Work directly with leading AI research labs on real production systems — not toy projects
  • Fully remote and flexible — structure your work around your life
  • Freelance autonomy with the depth and continuity of meaningful, long-term technical work
  • Make a direct, tangible impact on the AI systems shaping how the world uses technology
  • Potential for ongoing work and contract extension as new projects launch