Senior C# Code Reviewer

About OpenTrain

OpenTrain is the #1 platform for finding and building careers in AI training and data labeling. We connect contributors with projects that teach AI systems through human examples and quality review—helping people start and grow careers in a fast-growing, remote-friendly industry.

About AI Training Work

AI training (data labeling and human feedback) is the human side of building modern models. Contributors annotate, evaluate, and review model outputs so next-generation AI behaves safely and usefully. This role sits at the intersection of software engineering and quality assurance: your reviews directly shape the code the models learn from.

The Role

You will be a Senior C# Code Reviewer auditing annotator reviews of AI-generated C# code for Project Atlas. For each submission you will compile and run the snippet in an isolated container, confirm it follows the prompt, functions correctly, and meets performance and security best practices. You will correct mis-ratings, provide targeted feedback, and ensure every review aligns with the Project Atlas quality rubric.

What You'll Do

• Compile and execute AI-generated C# snippets in sandboxed/containerized environments to verify functionality and prompt compliance.
• Confirm correctness, performance, thread-safety, and secure-coding posture; identify injection, race conditions, unsafe casts, and deserialization flaws.
• Re-score or correct annotator reviews when ratings are inaccurate and document the rationale per the Project Atlas rubric.
• Write concise, constructive feedback so annotators and model trainers understand defects and remediation steps.
• Use unit/integration tests, Testcontainers, and debuggers to reproduce issues and validate fixes.
• Log issues and track follow-up using ticketing tools and checklist-based QA practices.

Requirements

This is a senior-level technical review role. Preserve the following mandatory qualifications exactly as listed.

• 7+ years professional C#/.NET development, QA, or dedicated code-review experience.
• Expert in modern C# (10–13) and .NET Core / ASP.NET (Core 6/7/8); deep knowledge of CLR internals and memory management.
• Strong mastery of async/await, LINQ, generics, dependency injection, and common framework patterns.
• Advanced testing and debugging: xUnit/NUnit/MSTest, Testcontainers, Moq, and coverage tools (Coverlet, dotCover).
• Skilled with Visual Studio/Rider debuggers and profiling tools (dotTrace, dotMemory).
• Proven ability to analyze concurrency (TPL, Channels), thread safety, high-throughput scenarios, and GC tuning.
• Ability to detect and mitigate OWASP-style risks (XSS, SQLi), deserialization flaws, race conditions, and privilege escalation.
• Familiar with MSBuild/Dotnet CLI, Dockerized builds, CI/CD (GitHub Actions, Azure DevOps), and PR-based code review workflows.
• Comfortable compiling/executing code in sandbox/container environments to validate functionality and prompt compliance.
• Experience with rubric-based scoring, checklist reviews, and ticketing/annotation tools (Jira, Asana).
• Excellent written English (B2+ CEFR) for concise feedback and mentoring.

Nice To Have

• Experience with LLM evaluation, RLHF pipelines, or prior work on AI/ML data-labeling projects.
• Familiarity with Testcontainers advanced scenarios, CI pipeline optimization, or automated security scanning tools.

Schedule, Pay, and How It Works

This is a remote, contract, part-time role expected to be 20+ hours per week and is open worldwide. Compensation is $25 USD per hour, paid per the project's contractor terms.

Work is asynchronous: you will pick up review tasks, compile and test code in isolated containers, complete rubric scoring, and supply feedback through the project's annotation platform. You will use standard ticketing and PR tools to communicate findings and escalate complex issues.