Full Stack Engineer (Node.js and React) in Deutschland

Pay: up to $100/hour

As a Full Stack Engineer (https://jobeax.com/link/JSd7UYCSg572jJDY + 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, https://jobeax.com/link/JSd7UYCSg572jJDY 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.

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.

Requirements

• 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 https://jobeax.com/link/JSd7UYCSg572jJDY 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 (https://jobeax.com/link/Z30sZYC3jcRenVso 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.

Skills: React, Debugging, Code review, https://jobeax.com/link/JSd7UYCSg572jJDY, Database Design (SQL/NoSQL), REST/GraphQL APIs, English, TypeScript, Performance Optimization, Authentication & Authorization

Open to candidates in: Germany, India, The United States

Interview language: English