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

What if your C# expertise could directly shape the infrastructure powering the world's most advanced AI systems? 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 next-generation models.

This is a fully remote, flexible contract role for an experienced engineer who wants to work on real production systems at the frontier of AI — not just maintain legacy code, but architect meaningful infrastructure that matters.

• Organization: Alignerr
• Type: Hourly Contract
• Location: Remote
• Commitment: 20–40 hours/week

• Design, build, and optimize high-performance C# systems that support 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 used in production AI environments
• Collaborate closely 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, robust fixes
• Participate in synchronous design reviews to iterate on architecture and implementation decisions

• Full-stack developer with a strong systems programming background and deep command of C#
• 3–5+ years of professional experience writing production-grade C# code, with familiarity with modern standards
• Solid grounding in performance optimization, concurrency (threading, atomics), and memory safety
• Native or fluent English speaker with clear written and verbal communication skills
• Self-directed and reliable — able to commit 20–40 hours per week and deliver consistently without hand-holding
• Comfortable navigating complex codebases and making principled architectural decisions under real constraints

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

• Work at the frontier of AI — your code will directly influence how the world's leading models are built and evaluated
• Fully remote and flexible — structure your hours around your life, not the other way around
• Collaborate with world-class research and engineering teams on genuinely hard problems
• Freelance autonomy with the substance of high-impact, technically demanding work
• Potential for ongoing work and contract extension as projects evolve and expand