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

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

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