Senior Full-Stack Engineer (React / Next.js + Supabase)

Description We have an existing consumer web platform approaching launch and are looking for a senior full-stack engineer to help ensure it is production-ready. This engagement focuses on reviewing, strengthening, and finalizing an existing codebase rather than building a product from scratch. Tech Stack • React / Next.js. • Supabase (Postgres, Auth, Realtime, Storage, Edge Functions). • Stripe. What you'll be doing • Perform a comprehensive audit of the existing codebase.. • Identify technical debt, architectural inconsistencies, security concerns, and areas that would benefit from refactoring.. • Review AI-assisted code and improve any sections that need production-quality implementation.. • Strengthen error handling, edge-case coverage, and overall code robustness.. • Optimize performance where it provides meaningful value.. • Refactor and implement the highest-priority improvements identified during the review.. • Help prepare the application for a stable production launch.. • Recommend practical improvements to the project's long-term architecture and development practices.. What we're looking for • Strong senior-level experience across the full stack with a track record of launching production web applications.. • Someone comfortable inheriting an existing codebase and improving it without introducing regressions.. • Good judgment about what should be refactored versus what should remain unchanged under launch deadlines.. • A clear communicator who can explain technical tradeoffs to a non-technical founder.. We value experience and judgment over hourly rate. This is a substantial launch-readiness engagement for the right engineer, with a well-defined scope and a decisive client. To apply, briefly describe a project where you reviewed, improved, or prepared an existing application for production launch.