Mid-Level Full-Stack Developer with QA

We are looking for a reliable full-stack developer to help maintain, QA, and build new features into an existing production web platform. This role is ideal for a mid-level developer who is comfortable working in an established codebase, following existing patterns, testing their work carefully, and shipping updates under senior management review. This is not a greenfield project. The right person should be careful, organized, and able to make steady improvements without breaking existing functionality. Responsibilities Build and update features in an existing Next.js, React, TypeScript codebase. Work with Supabase for database queries, auth flows, migrations, edge functions, and scheduled jobs. Update UI using Tailwind CSS, shadcn/Radix UI components, and existing design patterns. QA all assigned work before handoff, including desktop/mobile checks, edge cases, and regression testing. Write or update tests where appropriate using Vitest and help improve automated test coverage over time. Debug production issues across frontend, backend functions, email automation, payment flows, and admin dashboards. Work safely with integrations such as Stripe, email services, Shopify, OpenAI, and third-party APIs. Submit clean pull requests with clear notes, screenshots/videos when useful, and a short QA checklist. Avoid unnecessary rewrites; follow existing architecture and ask before making major structural changes. Required Skills 2-4+ years of practical experience with React, Next.js, TypeScript, and modern frontend development. Comfortable reading and safely modifying a large existing codebase. Experience with Supabase, PostgreSQL, or similar backend/database systems. Ability to understand auth, permissions, server actions/API routes, database migrations, and edge/serverless functions. Strong debugging habits and attention to detail. Basic automated testing experience with tools like Vitest, React Testing Library, or Playwright. Git workflow experience: branches, pull requests, code review, resolving merge issues. Good written communication and ability to explain what changed, how it was tested, and what risks remain. Nice To Have Experience with Stripe checkout/webhooks/subscriptions. Experience with email automation, lifecycle marketing, or CRM-style workflows. Experience with Supabase Edge Functions or Deno-style serverless functions. Experience with CMS/admin tools, dashboards, drag-and-drop builders, or automation editors. Familiarity with AI/OpenAI integrations. Experience setting up or expanding end-to-end QA with Playwright. What We Do Not Want Someone who blindly rewrites large parts of the app. Someone who only knows tutorials and cannot debug independently. Someone who ships without testing. Someone who changes database migrations, auth, payments, or email automation without review. Someone who over-engineers simple features. Ideal Candidate The ideal candidate is not necessarily a senior architect, but they must be careful, honest about what they do not know, and consistent about QA. They should be able to complete scoped tickets independently, ask good questions early, and work under senior review without creating instability in the repo.