Senior Backend Engineer (C#) - AI Data Platform

About The Role

What if your C# engineering skills could directly shape the infrastructure powering the world's most advanced AI systems? We're looking for a Senior C# Engineer to design and build the data pipelines, annotation tooling, and evaluation infrastructure that leading AI labs depend on to train and improve next-generation models.

This is a fully remote, flexible contract role working on real production systems at the frontier of AI development. If you're a seasoned backend engineer who wants meaningful, high-impact work — this is it.

• 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 model evaluation workflows
• Develop backend services and tooling 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 infrastructure
• Identify bottlenecks and edge cases in data and system behavior, then implement scalable, production-ready fixes
• Participate in synchronous design reviews to iterate on architecture and implementation decisions

• Native or fluent English speaker with clear written and verbal communication skills
• 5+ years of professional experience building scalable backend services in C#
• Strong systems programming background with full-stack development experience
• Deep expertise in modern frameworks for RESTful APIs and RPC services
• Experienced integrating cloud-native data services and orchestrating workflows via message bus architectures
• Able to commit 20–40 hours per week with reliability and consistency

• Prior experience with data annotation, data quality pipelines, or model evaluation systems
• Familiarity with AI/ML workflows, model training, or benchmarking infrastructure
• Background in distributed systems design or developer tooling

• Work directly on cutting-edge AI projects alongside the world's leading research labs
• Fully remote and flexible — structure your hours around your life
• Freelance autonomy with the substance of high-impact, technically challenging work
• Contribute to infrastructure that shapes the future of AI at a foundational level
• Potential for ongoing engagement and expanded scope as new projects launch