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

Posted 3 Mar 2026

$50–75/hr

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Work

Remote · Contract

Experience

3+ years

Eligibility

No stated location restriction

Field

Software engineering

Skills

C#Full-Stack DevelopmentSystems ProgrammingBackend DevelopmentData PipelinesData Annotation SystemsData ValidationQuality ControlPerformance OptimizationConcurrencyThreadingAtomic OperationsMemory SafetyDistributed SystemsDeveloper ToolingAI/ML WorkflowsModel Training PipelinesBenchmarking SystemsEnglish

About this role

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

About the Role

What if your C# expertise could directly shape the systems that power the world's most advanced AI models? We're looking for a Senior C# Full-Stack 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 AI.

This is a fully remote contract role working on real production systems — not toy problems. You'll collaborate with data, research, and engineering teams at the frontier of AI development, solving genuinely hard infrastructure and systems challenges at scale.

  • 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 to iterate on system architecture and implementation decisions

Who You Are

  • Full-stack developer with a strong systems programming background and deep C# expertise
  • 3–5+ years of professional experience writing production C# code with a focus on modern standards
  • Solid understanding of performance optimization, concurrency (threading, atomics), and memory safety
  • Clear and precise written and verbal communicator — you can articulate technical decisions confidently
  • Native or fluent English speaker
  • Available 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 pipelines, or benchmarking systems
  • Experience with distributed systems or developer tooling
  • Background working with or alongside research teams in fast-moving technical environments

Why Join Us

  • Work directly on cutting-edge AI systems used by leading research labs
  • Fully remote and flexible — structure your work around your life
  • Freelance autonomy with the depth and impact of high-stakes engineering work
  • Collaborate with world-class engineers and researchers on problems that actually matter
  • Potential for ongoing work and contract extension as projects evolve and expand

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