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

Alignerr Corp.; Seattle (WA); Remote; USD 83,000 - 138,000; Part time

Benefits offered by this job

Fully remote

Freelance autonomy

Flexible schedule

Job summary

Alignerr is seeking a Senior C# Full-Stack Engineer for a fully remote hourly contract. The role focuses on building and optimizing data pipelines, annotation tooling, and evaluation systems used by AI research teams. Expect 20–40 hours per week with production impact and high technical depth.

You will collaborate with data, research, and engineering teams, tackling performance, concurrency, and memory-safety challenges while delivering scalable, production-ready solutions.

Qualifications

• 3–5+ years professional production C# experience.
• Strong systems programming background with focus on performance.

Responsibilities

• Design, build, and optimize high-performance C# systems for AI data pipelines and evaluation workflows.
• Develop full-stack tooling and backend services for large-scale data annotation and quality control.
• Improve reliability, performance, and memory safety across codebases.
• Collaborate with data, research, and engineering teams to support model training workflows.
• Identify bottlenecks and implement scalable, production-ready fixes.
• Participate in design reviews to iterate on architecture decisions.

Skills

C#

Full-stack

Performance optimization

Concurrency

Job description

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 every day. This is a fully remote contract role with meaningful technical depth and real production impact. You'll work alongside data, research, and engineering teams at the frontier of AI development - solving hard problems 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 — then implement scalable, production-ready fixes
• Participate in synchronous design and code reviews to iterate on system architecture and implementation decisions

Who You Are

• Native or fluent English speaker with clear written and verbal communication skills
• Experienced full-stack developer with a strong systems programming background
• 3–5+ years of professional experience writing production C# with a focus on modern standards
• Deep understanding of performance optimization, concurrency (threading, atomics), and memory safety
• Self-directed and reliable — able to commit 20–40 hours per week and deliver without hand-holding

Nice to Have

• Prior experience with data annotation, data quality, or evaluation systems
• Familiarity with AI/ML workflows, model training, or benchmarking pipelines
• Experience with distributed systems or developer tooling
• Background in C++17/C++20 or other systems-level languages

Why Join Us

• Work on real production systems used by leading AI research labs
• Fully remote - work from anywhere, on a schedule that suits you
• Freelance autonomy with the structure of impactful, technically demanding work
• Contribute to infrastructure that directly influences how next-generation AI models are built and evaluated
• Potential for ongoing work and contract extension as new projects launch