Software Engineer (C#) - Internal Tooling

New York

**Software Engineer (C#) --- Internal Tooling (AI Infrastructure)** **About The Role** What if your C# expertise could directly shape the infrastructure powering the world's most advanced AI systems? We're looking for experienced C# full-stack engineers to build and optimize the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on. This is a fully remote contract role with meaningful technical scope --- real production systems, high-impact workflows, and the kind of engineering problems that actually stretch your skills. * 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, and implement scalable, production-ready fixes * Participate in synchronous design reviews and iterate on system architecture decisions with senior engineers **Who You Are** * Native or fluent English speaker with clear written and verbal communication skills * Full-stack developer with a strong systems programming background * 3--5+ years of professional experience writing production-grade C# * Experienced in interoperability scenarios --- such as invoking Python ML models from .NET or wrapping native libraries * Skilled at designing robust benchmarking and evaluation harnesses * Able to commit 20--40 hours per week consistently **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 working directly with or alongside AI research teams **Why Join Us** * Work on cutting-edge AI infrastructure alongside leading research labs * Fully remote and flexible --- work from wherever you do your best engineering * Freelance autonomy with the structure and consistency of ongoing, meaningful project work * Tackle genuinely hard technical problems with real-world impact on AI systems at scale * Potential for ongoing work and contract extension as new projects launch