React + Node Developer — Onboarding Quiz Flow with Firebase Auth + Stripe

We need a developer to build a multi-step onboarding quiz as a standalone React app (Vite) that authenticates through Firebase, processes payments through Stripe, and sends data to our existing Node.js API. The project: A 9-step onboarding flow for a subscription app. Steps include text inputs, single-select and multi-select questions, a registration screen (Firebase Auth), a plan selection screen, and a payment screen (Stripe Elements). The app deploys as static files to a subdirectory on our existing WordPress domain. No WordPress integration needed — it's a standalone React app that lives in its own folder on the same server. What's already in place: Firebase project with Auth configured, a Node.js API server connected to a Postgres/MySQL database, a React Native iOS app that already talks to this API, a Stripe account, brand design and all quiz content finalized, and a detailed architecture document with file structure and data flow. Frontend work: — Build the multi-step quiz in React (Vite, React Router) — Firebase Auth integration (email/password + Google SSO) — Stripe Elements for the payment screen — POST quiz answers to our existing Node API on completion — Responsive CSS matching our brand design from screenshots Backend work (small scope): — Add an endpoint to receive and store quiz/onboarding answers — Add an endpoint to create Stripe payment intents — Add an endpoint to push new user data to HubSpot's API — All endpoints added to our existing Node.js server Must have: — React (hooks, functional components, React Router) — Node.js / Express (adding endpoints to an existing server) — Postgres or MySQL (writing queries or working with an existing ORM) — Firebase Auth (email/password + Google SSO) — Stripe Elements (@stripe/react-stripe-js) and server-side Stripe SDK — Responsive CSS (must match existing brand design from screenshots) — Experience building multi-step form flows Nice to have: — Vite — HubSpot API experience — Statsig or similar experimentation platform — AWS deployment experience (server is hosted on AWS) Job Type: Part-time Pay: $100.00 - $120.00 per hour Work Location: Remote