Back to jobs

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

$50-75/hrRemoteFreelanceCODING

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 C# Full-Stack Engineer to build and optimize the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on — working on real production systems with genuine, measurable impact.

This is a fully remote contract role with flexible hours. If you're a sharp systems thinker who loves solving hard infrastructure problems, this is the kind of work that will actually push you.

  • 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 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 safety across existing C# codebases — hunt down bottlenecks and ship scalable fixes
  • Collaborate directly with data, research, and engineering teams to support model training and evaluation workflows
  • Identify edge cases and systemic issues in data and system behavior and implement robust solutions
  • Participate in synchronous design reviews to iterate on architecture and implementation decisions

Who You Are

  • Full-stack developer with a strong systems programming background and 3–5+ years of professional C# experience
  • Confident writing production-quality code with a focus on modern C# standards and best practices
  • Deep understanding of performance optimization, concurrency (threading, atomics), and memory safety
  • Clear, precise written and verbal communicator — you can articulate technical decisions without hand-waving
  • Self-directed and reliable when working remotely with minimal supervision
  • Native or fluent English speaker
  • Able to commit 20–40 hours per week on a consistent basis

Nice to Have

  • Prior experience with data annotation, data quality pipelines, or AI 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 applied ML environments

Why Join Us

  • Work directly with leading AI labs on cutting-edge production systems — not toy projects
  • Fully remote and flexible — structure your work around your life
  • Freelance autonomy with the focus and momentum of high-impact engineering work
  • Collaborate with world-class data, research, and engineering teams pushing the frontier of AI
  • Potential for ongoing work and contract extension as projects scale