Senior Backend Engineer (C#) - AI Data Platform

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 Backend Engineer to design and build the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and improve their models.

This is a fully remote contract role with flexible scheduling — and the work is anything but routine. You'll be embedded in real production systems, solving hard engineering problems at the intersection of scale, performance, and AI.

• 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 backend services and full-stack tooling for large-scale data annotation, validation, and quality control
• Improve reliability, performance, and safety across existing C# codebases used in production AI systems
• 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, elegant 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 mastery of modern frameworks for RESTful APIs and RPC services for inter-service communication
• Experienced integrating with cloud-native data services and orchestrating workflows via message bus architectures
• Self-directed and reliable — you can commit to 20–40 hours per week and deliver without hand-holding

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

• Work on cutting-edge AI infrastructure alongside world-class research labs
• Fully remote and flexible — work on your own schedule from anywhere
• Freelance autonomy with the substance of genuinely high-impact engineering work
• Contribute to systems that directly influence how next-generation AI models are built and evaluated
• Potential for ongoing work and contract extension as new projects launch