Full-Stack React Engineer | $75/hr | Remote

Senior Full-Stack React Engineers, QA Automation & AI Evaluation Experts.We are seeking experienced senior full-stack engineers, React developers, software testing specialists, and automation engineers to build secure coding environments used to evaluate advanced AI agents.You will work with realistic website clones, identify bugs, write technical specifications, and develop automated grading systems that determine whether AI-generated code correctly solves complex software engineering tasks.What You’ll DoReview realistic web application clones and identify bugs, missing functionality, and workflow gapsWrite detailed technical specifications for complex full-stack coding tasksBuild comprehensive automated test suites for AI-generated codeDesign grading logic that produces accurate and deterministic pass or fail outcomesTest frontend, backend, API, database, authentication, and application-state behaviorIdentify shortcuts, exploits, hidden dependencies, and ways an AI agent could bypass intended requirementsStrengthen evaluation environments so grading cannot be easily manipulatedDebug unreliable tests, race conditions, asynchronous failures, and edge casesReview how AI agents interact with tasks and improve the evaluation methodologyCreate reproducible, isolated, and maintainable development environmentsDocument expected behavior, test coverage, assumptions, and reference solutionsWho Can ApplyRelevant backgrounds include:Senior Full-Stack Engineers, Full-Stack Software Engineers, Senior Software Engineers, Staff Software Engineers, Principal Software Engineers, Lead Software Engineers, Full-Stack Developers, Web Application Engineers, Product Engineers, Application Developers, and Software Development Consultants.Frontend and React backgrounds may include:Senior React Developers, React Engineers, Frontend Engineers, Senior Frontend Engineers, JavaScript Engineers, TypeScript Engineers, UI Engineers, Web Engineers, React Architects, Frontend Architects, Design Systems Engineers, and Client-Side Application Engineers.Backend and platform backgrounds may include:Backend Engineers, Node.js Engineers, API Engineers, Platform Engineers, Infrastructure Engineers, Systems Engineers, Cloud Engineers, Developer Productivity Engineers, Developer Experience Engineers, DevOps Engineers, and Site Reliability Engineers.Testing and quality backgrounds may include:QA Automation Engineers, SDETs, Software Development Engineers in Test, Test Automation Engineers, Quality Engineers, Software Test Engineers, UI Automation Engineers, End-to-End Test Engineers, Browser Automation Engineers, Test Infrastructure Engineers, Test Framework Engineers, QA Architects, Test Architects, and Quality Engineering Leads.Security and evaluation backgrounds may include:Application Security Engineers, Web Security Engineers, Product Security Engineers, Penetration Testers, Security Researchers, Red Team Engineers, Secure Coding Specialists, AI Evaluation Engineers, Model Evaluation Specialists, Benchmark Engineers, AI Safety Engineers, and Human Data Specialists.RequirementsSenior-level professional experience in full-stack software engineeringDeep hands-on experience building web applications with ReactStrong JavaScript or TypeScript skillsExperience developing or maintaining backend services, APIs, and databasesStrong experience with automated testing and browser-based test frameworksAbility to write detailed technical specifications and acceptance criteriaStrong debugging and code-review skillsUnderstanding of test isolation, reproducibility, deterministic execution, and reliable assertionsAbility to anticipate edge cases, unintended behaviors, and potential evaluation bypassesStrong written communication and attention to technical detailAvailability for an ongoing, high-commitment remote engagementPreferred BackgroundExperience designing end-to-end testing frameworksExperience reviewing AI-generated code or evaluating coding agentsBackground in web security, application security, or secure test designExperience building coding benchmarks, technical assessments, or automated grading platformsExperience testing realistic website clones or complex production applicationsExperience with sandboxed execution environments and containerized applicationsExperience creating golden reference implementations or reference solutionsExperience reviewing the work of other senior engineersThis opportunity is ideal for senior engineers who can build realistic web applications, identify subtle bugs, design rigorous automated tests, and create evaluation systems that accurately measure whether an AI agent has truly solved a coding task. We are a referral partner of the client