React Developer — Healthcare Assessment Web App (Scoring Engine, Supabase, HubSpot, Stripe)

We are a healthcare advisory firm launching a standalone scoring application and need a full-stack developer who builds precisely to spec and ships fast. This is a self-contained build with its own repo and deployment; it does not touch our existing marketing website. The product is a multi-step assessment that scores a practice across 10 weighted dimensions and returns a score, with a results view showing the score band. A working HTML build of the assessment already exists, with the question flow, scoring, design, and copy complete. We need it to be deployed, verified, hardened, and integrated. Scope, in build order: Demo deploy: hard deadline. Stand up the provided HTML assessment as its own Vercel project with deployment protection (password) enabled and a shareable URL. Fully functional client-side per the provided file, clean on desktop and mobile, no console errors. Due within 3 business days of file handoff. Do not apply if you cannot meet this. Scoring verification and edge cases. Confirm scoring output matches the test file we provide (defined inputs, expected score and band as outputs). Handle partial answers, refresh mid-flow, and back navigation. Scoring internals are proprietary; you will verify against the black-box test cases, not a formula document. Server-side migration + Supabase. Move scoring logic out of client-side JavaScript into a server-side function. Supabase data layer: submissions, scores, and leads persist. Supabase Auth with email magic link, Google, and Microsoft sign-in (no SAML); users can sign up, log out, and log back into a saved score. Integrations and production. HubSpot lead created on submission with defined contact properties. Stripe Checkout for the paid report tier, recorded on the HubSpot contact. Cross-browser QA and production deploy. How we work: We provide the files and the test cases; you build from them verbatim. If you believe something should be done differently, flag it in writing and we decide. Do not substitute your own interpretation. Acceptance is verified against the provided files and test cases in an incognito session before any milestone releases. A signed confidentiality and IP assignment agreement is required before project files are transferred; the first milestone clock starts at file handoff, not contract award. Requirements: Strong React/Next.js and vanilla JS (the existing build is static HTML/JS). Supabase (data + auth) in production. HubSpot API experience. Stripe Checkout experience. Show 2–3 live web applications you built (not WordPress or page-builder sites). Available to start within 24 hours with daily progress visible on the preview URL. Fixed price, milestone-based. Do not apply if you plan to use WordPress, Wix, or any page builder.