Software Engineer (C#) - Internal Tooling

Alignerr; Mexico; On-site; PHP 5,156,000 - 9,453,000; Part time

Benefits offered by this job

Fully remote

Freelance autonomy

Contract extension potential

Job summary

Alignerr is seeking a senior full-stack C# engineer to build data pipelines, annotation systems, and evaluation tooling powering AI infrastructure. You will write production code at the heart of AI training and evaluation workflows—the kinds of systems that determine how models learn, improve, and get measured.

This is a remote hourly contract offering 20–40 hours per week. You will collaborate with data, research, and engineering teams across model training and evaluation, delivering scalable,

Qualifications

• 3–5+ years of production-grade C# experience.
• Clear and precise written and verbal communication in English.
• Ability to commit 20–40 hours per week consistently.

Responsibilities

• Design and build high-performance C# systems for 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 correctness across existing C# codebases.
• Build benchmarking and evaluation harnesses to measure system behavior.
• Implement interoperability solutions — calling Python ML models from .NET or wrapping native libraries.
• Identify bottlenecks and ship scalable, well-reasoned fixes.
• Collaborate with data, research, and engineering teams across model training and evaluation workflows.

Skills

C# development

Full-stack development

Python interop

Benchmarking

Performance tuning

Job description

Software Engineer (C#) — Internal Tooling (AI Infrastructure)

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 full-stack C# engineer to build the data pipelines, annotation systems, and evaluation tooling that leading AI labs depend on every day.

This isn't toy work or proof-of-concept territory. You'll be writing production code that sits at the heart of real AI training and evaluation workflows — the kind of systems that determine how models learn, improve, and get measured.

• Organization: Alignerr
• Type: Hourly Contract
• Location: Remote
• Commitment: 20–40 hours/week

What You'll Do

• Design and build high-performance C# systems that support 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 correctness across existing C# codebases
• Build robust benchmarking and evaluation harnesses to measure system behavior
• Implement interoperability solutions — such as invoking Python ML models from .NET or wrapping native libraries
• Identify bottlenecks and edge cases, then ship scalable, well-reasoned fixes
• Collaborate with data, research, and engineering teams across model training and evaluation workflows
• Participate in synchronous design reviews to iterate on architecture and implementation decisions

Who You Are

• 3–5+ years of professional experience writing production-grade C#
• Strong full-stack developer with a solid systems programming foundation
• Experienced in interoperability scenarios — calling Python ML models from .NET, wrapping native libraries, bridging ecosystems
• Proven track record designing benchmarking harnesses and performance evaluation systems
• Clear, precise written and verbal communicator — you can explain technical decisions to mixed audiences
• Native or fluent English speaker
• Able to commit 20–40 hours per week consistently

Nice to Have

• Prior experience with data annotation platforms, data quality pipelines, or 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 AI-adjacent engineering environments

Why Join Us

• Work on real production systems alongside top AI research labs — not toy demos
• Fully remote and flexible — structure your hours around your best work
• Freelance autonomy with the substance of meaningful, high-stakes engineering
• Make a tangible impact on the infrastructure that shapes how next-generation AI models are built and evaluated
• Potential for ongoing work and contract extension as projects grow