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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? 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 every day.

This is a fully remote contract role with meaningful technical depth and real production impact. You'll work alongside data, research, and engineering teams at the frontier of AI development — solving hard problems at scale.

  • 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 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 — then implement scalable, production-ready fixes
  • Participate in synchronous design and code reviews to iterate on system architecture and implementation decisions

Who You Are

  • Native or fluent English speaker with clear written and verbal communication skills
  • Experienced full-stack developer with a strong systems programming background
  • 3–5+ years of professional experience writing production C# with a focus on modern standards
  • Deep understanding of performance optimization, concurrency (threading, atomics), and memory safety
  • Self-directed and reliable — able to commit 20–40 hours per week and deliver without hand-holding

Nice to Have

  • 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 tooling
  • Background in C++17/C++20 or other systems-level languages

Why Join Us

  • Work on real production systems used by leading AI research labs
  • Fully remote — work from anywhere, on a schedule that suits you
  • Freelance autonomy with the structure of impactful, technically demanding work
  • Contribute to infrastructure that directly influences how next-generation AI models are built and evaluated
  • Potential for ongoing work and contract extension as new projects launch