Full Stack Engineer (Node.js and React)

SME Careers; Deutschland; Remote; EUR 55,000 - 96,000; Part time

Job summary

SME Careers is seeking a Full Stack Engineer (Node.js + React) for a fully remote, hourly paid contractor role. You will review AI-generated code, system designs, and explanations, and produce high-quality reference implementations and step-by-step reasoning.

You will assess solutions for correctness, security, performance, scalability, and adherence to prompts; identify API design, authentication, data modeling, React rendering, Node.js runtime behavior, and testing, CI/CD, observability, and

Qualifications

• Bachelor’s degree in Computer Science or related field, or equivalent experience.
• 4+ years building production web apps with Node.js and React.
• Proficient in TypeScript for backend and frontend.

Responsibilities

• Review AI-generated code, designs, and explanations for quality.
• Create reference implementations and step-by-step reasoning.
• Assess API design, security, performance, and observability.

Skills

Node.js

React

TypeScript

CI/CD

Testing

Education

Bachelor’s degree in Computer Science or related field

Tools

Express

NestJS

Fastify

Prisma

TypeORM

Next.js

Playwright

Cypress

Jest/Vitest

Job description

As a Full Stack Engineer (Node.js + React), you will work remotely on an hourly paid basis to review AI-generated full-stack code, system designs, and technical explanations, as well as produce high-quality reference implementations and step-by-step reasoning for complex engineering problems. You will assess solutions for correctness, clarity, security, performance, scalability, and adherence to the prompt; identify issues in API design, authentication/authorization, data modeling, React rendering/state, Node.js runtime behavior, async/concurrency, error handling, testing, and observability; fact-check technical information; write high-quality explanations and model solutions that demonstrate best practices; and rate and compare multiple AI responses based on correctness and reasoning quality.

This fully remote, hourly paid contractor role is with SME Careers, a fast-growing AI data services company and subsidiary of SuperAnnotate that provides AI training data to many of the world’s largest AI companies and foundation model labs—where your frontend expertise will directly help improve the world’s premier AI models used by millions of developers worldwide.

Important

There is no immediate project for this role; however, if qualified, you will be among the first experts we reach out to when relevant opportunities arise. This will also provide you with access to future projects available through our expert network.

Key Responsibilities

• Develop AI Training Content: Create detailed prompts across full-stack topics and write high-quality reference answers to guide AI learning.
• Optimize AI Performance: Evaluate and rank AI responses to enhance correctness, security, performance, and maintainability.
• Ensure Model Integrity: Test AI outputs for inaccuracies or unsafe recommendations, validating reliability across real-world use cases.

Your Profile

• Bachelor’s degree or higher in Computer Science, Software Engineering, or a closely related technical field (or equivalent practical experience).
• 4+ years of professional experience building production web applications, including Node.js backend and React frontend.
• Strong proficiency in TypeScript across both backend and frontend codebases.
• Backend expertise in Node.js: async patterns, event loop behavior, API design, validation, error handling, security, and background jobs/queues.
• Frontend expertise in React: hooks, component patterns, state management, performance optimization, forms, and accessibility basics.
• Experience designing and operating data layers: PostgreSQL/MySQL and/or MongoDB, schema design, migrations, indexing, and query optimization.
• Experience with authentication flows: sessions vs JWT, cookies, OAuth/OIDC basics, RBAC/ABAC concepts, and secure secrets handling.
• Strong testing culture: unit/integration/E2E testing (e.g., Jest/Vitest, React Testing Library, Playwright/Cypress) and CI/CD workflows.
• Familiarity with modern stack tooling: Express/Fastify/NestJS, ORMs (Prisma/TypeORM), and React frameworks (Next.js is a plus).
• Minimum C1 English proficiency (written and spoken), with the ability to write clear technical explanations and follow detailed English-language guidelines.
• Previous experience with AI data training, annotation, or evaluating AI-generated technical content is a strong plus.
• Highly detail-oriented and systematic, with a methodical approach to evaluating reasoning quality and identifying subtle issues in complex full-stack code.