Software Engineer (C#) — Internal Tooling (AI 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 full-stack C# engineer to build the data pipelines, annotation systems, and evaluation tooling that leading AI labs depend on every day. This isn't toy work or proof-of-concept territory. You'll be writing production code that sits at the heart of real AI training and evaluation workflows — the kind of systems that determine how models learn, improve, and get measured.
• Organization: Alignerr
• Type: Hourly Contract
•

Location:
Remote
• Commitment: 20–40 hours/week

What You'll Do
• Design and build high-performance C# systems that support large-scale AI data pipelines and evaluation workflows
• Develop full-stack tooling and backend services for data annotation, validation, and quality control at scale
• Improve reliability, performance, and correctness across existing C# codebases
• Build robust benchmarking and evaluation harnesses to measure system behavior
• Implement interoperability solutions — such as invoking Python ML models from .
NET or wrapping native libraries
• Identify bottlenecks and edge cases, then ship scalable, well-reasoned fixes
• Collaborate with data, research, and engineering teams across model training and evaluation workflows




• Participate in synchronous design reviews to iterate on architecture and implementation decisions Who You Are
• 3–5+ years of professional experience writing production-grade C#
• Strong full-stack developer with a solid systems programming foundation
• Experienced in interoperability scenarios — calling Python ML models from .
NET, wrapping native libraries, bridging ecosystems
• Proven track record designing benchmarking harnesses and performance evaluation systems
• Clear, precise written and verbal communicator — you can explain technical decisions to mixed audiences
• Native or fluent English speaker
• Able to commit 20–40 hours per week consistently Nice to Have
• Prior experience with data annotation platforms, data quality pipelines, or evaluation systems
• Familiarity with AI/ML workflows, model training, or benchmarking infrastructure
• Experience with distributed systems or developer tooling
• Background working in fast-moving research or AI-adjacent engineering environments Why Join Us
• Work on real production systems alongside top AI research labs — not toy demos
• Fully remote and adaptable — structure your hours around your best work
• Freelance autonomy with the substance of meaningful, high-stakes engineering
• Make a tangible impact on the infrastructure that shapes how next-generation AI models are built and evaluated
• Potential for ongoing work and contract extension as projects grow

📌 Software Engineer (México)
🏢 Alignerr
📍 México