Full-Stack Developer (Next.js + Supabase) — Marketplace SaaS — MVP to Production-Ready

We have a working MVP for a marketplace/platform SaaS product and are looking for a skilled full-stack developer to take it from "functional prototype" to a polished, scalable product users love. This is not a greenfield build the codebase exists, the core flows work, and early users are testing it. We need someone who can step in, understand what's already built, and systematically improve it. The Stack Frontend: Next.js (App Router), React, Tailwind CSS Backend: Supabase (Auth, Database, Edge Functions) / Firebase Hosting: Vercel Payments: Stripe (or similar) What You'll Be Doing Review the existing codebase and identify areas for improvement (architecture, performance, security) Build out remaining features on the product roadmap Improve the UI/UX for both sides of the marketplace (buyers and sellers) Implement robust search, filtering, and matching logic Set up proper error handling, logging, and monitoring Optimize database queries and implement Row Level Security (RLS) in Supabase Write clean, well-documented, maintainable code Implement responsive design and ensure cross-browser compatibility Set up CI/CD pipeline and staging environment You're a Great Fit If You Have 3+ years of production experience with Next.js and React Hands-on experience with Supabase (Auth, Postgres, Edge Functions, RLS) or Firebase Experience building two-sided marketplaces or platforms (this is a big plus) Strong understanding of relational database design and query optimization Experience with Stripe or similar payment integrations A portfolio or GitHub showing shipped products — not just tutorials Familiarity with real-time features (notifications, messaging, live updates) Solid understanding of authentication flows, role-based access, and security best practices Good communication skills and comfort working asynchronously FIXED PRICE-100 , "I will hire 2 developers for this job, $100 each."