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

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

• 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

• 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

• 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

• 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