Full-Stack Code Reviewer — Node.js & React

About OpenTrain

OpenTrain is the #1 platform for people building careers in AI training and data labeling. We connect skilled contributors with technical projects that shape how modern AI behaves, letting you build a portfolio, access ongoing opportunities, and grow your work in a fast-moving industry.

This role is hired and managed by OpenTrain. You will contribute to improving AI systems by using your engineering judgment to evaluate, correct, and teach through reference answers and model solutions.

Why AI training work matters

AI models learn from examples and human feedback: reviewers check outputs, produce accurate references, and rate model reasoning so systems improve. This work is remote, flexible, and accessible—especially for experienced engineers who want to apply their expertise in a high-impact, part-time capacity.

As a full-stack reviewer you’ll directly influence how models handle real engineering tasks: correctness, security, performance, and clarity all depend on careful human evaluation.

The role

You will review AI-generated full-stack code, system designs, and technical explanations, then produce high-quality reference implementations and step-by-step reasoning for complex engineering problems. The focus spans Node.js backend behavior and React frontend correctness, plus cross-cutting concerns like API design and authentication.

This is contractor, hourly-paid work done remotely. You’ll be asked to compare multiple AI responses, identify errors, test outputs in realistic scenarios, and write clear, reproducible reference answers that other reviewers and models can learn from.

What you’ll do (key responsibilities)

• Review AI-generated full-stack code, architectures, and explanations for correctness and best practices.
• Write reference implementations and model solutions for backend and frontend problems.
• Evaluate outputs for security, performance, scalability, and prompt adherence.
• Identify issues in API design, authentication/authorization, data modeling, and error handling.
• Assess React rendering, hooks, state management, forms, and accessibility basics.
• Test AI outputs for unsafe or inaccurate engineering recommendations.
• Create detailed prompts and high-quality reference answers for full-stack topics.
• Compare multiple AI responses and rate them based on reasoning quality and technical accuracy.

Requirements

We need engineers with hands-on production experience and strong TypeScript skills across backend and frontend codebases. You must be able to write clear technical explanations in English and apply systematic code-review reasoning.

• Strong professional experience building production web applications with Node.js and React.
• Advanced TypeScript fluency across backend and frontend codebases.
• Backend knowledge of async patterns, the event loop, API design, validation, and error handling.
• Frontend expertise with hooks, component patterns, state management, performance optimizations, forms, and basic accessibility.
• Experience with PostgreSQL, MySQL, or MongoDB including schema design, migrations, indexing, and query optimization.
• Experience with authentication flows (sessions, JWT, cookies, OAuth/OIDC), RBAC/ABAC, and secure secrets handling.
• Strong testing culture across unit, integration, and E2E testing, plus CI/CD workflow familiarity.
• Minimum C1 English proficiency for writing clear technical explanations.
• Previous AI data-training, annotation, or model-evaluation experience is a strong plus.

Helpful background

Familiarity with frameworks and tools such as Express, Fastify, NestJS, Prisma, TypeORM, or Next.js will help you move faster in this role. A methodical, debuggers-first approach to reasoning and code review is highly valued.

Pay, time commitment, and logistics

This is an hourly contractor position with flexible scheduling. The expected minimum commitment is 20+ hours per week. OpenTrain has multiple hiring countries across Asia, Europe, North America, and South America and this listing includes 850 total openings.

Pay varies by country across three tiers: up to $40/hr, up to $60/hr, or up to $100/hr depending on country. The role is remote and contractor-based; applicable hourly tiers will be communicated during hiring.

• Employment types: Contractor, Part-time.
• Language requirement: English (C1 minimum).
• Time requirement: 20+ hours/week.
• Countries included: VN, TL, TH, SG, PK, PH, NP, MY, LK, KH, ID, BT, BD, IN, BR, DE, US.

How the process works

You will receive task briefs and AI outputs to review in our evaluation platform, compare responses, and submit rated evaluations plus reference implementations. Work is paid hourly according to your assigned tier and location.

OpenTrain provides ongoing opportunities for contributors who demonstrate consistent quality and domain expertise; producing clear, well-tested reference answers increases your chances for more work.

• Tasks include evaluation ratings, text generation of reference answers, and RLHF-style feedback.
• Label types: EVALUATION_RATING, TEXT_GENERATION, RLHF.