React developer to turn a working assessment portal prototype into a hosted, multi-client web app

About the project I have a fully working front-end prototype of a B2B assessment portal (single-file React app). The questions, scoring logic, reports and remediation views are all built and proven. I need an experienced developer to turn it into a proper multi-tenant web application with a backend, user accounts and a database — built so a separate company I appoint later can host and maintain it. What already exists A single-file React prototype (~2,000 lines) with all UI, branding and logic working in-browser. A defined data model: ~116 weighted assessment questions in four categories, each with a severity weighting. A working scoring engine (severity-weighted, four-state answers, RAG banding), a dashboard/heatmap report, and a remediation/action-tracking view. Two assessment levels (programme and project), two scope tiers (standard and full), and six sector variants applied as overlays. I'll provide the full file and a written walkthrough on day one. What I need built A real backend and database (persisted assessments, not browser storage). User accounts and roles (admin/consultant and client views), secure login. Multi-tenant separation so each client sees only their own data. The existing scoring, reports and remediation flows carried over exactly — no logic changes without sign-off. CSV/PDF export of reports and the remediation plan. Tech expectations React (18/19) + TypeScript, a modern backend (Node or similar), a real database (Postgres/Supabase/Firebase acceptable), proper auth. Tailwind fine. All code in my GitHub repo from day one. Experience building secure, multi-tenant apps with GDPR in mind. Hosting & handover I will appoint a separate hosting/maintenance company later, so I am not asking you to host it. Build it to be handed over cleanly to a third party: No lock-in to your own accounts or services; runnable by another provider in a UK/EU region. Deliver the full code repository, deployment/setup documentation (a runbook), and all credentials and environment config transferred to me. A clean, reproducible deployment process documented so another firm can stand it up without rebuilding. Paid trial task (first milestone) Before the full engagement: take the existing question/scoring data, stand up a minimal backend with login, save one completed assessment to a database, and re-render its score. Small, paid at your hourly rate. I'll judge code quality and communication from this. Milestones Paid trial (above). Backend, database schema, auth + roles. Assessment capture + scoring + reports ported and matching the prototype. Remediation tracking, exports, multi-tenant separation. Documentation, repo + credentials handover, and a reproducible deploy a third party can run. Budget & terms ~$25/hr, milestone-based. Ongoing hosting and maintenance will be handled separately by another company, but occasional paid development support afterwards is possible. To apply, please include Two live React apps you've shipped that have a backend and login (links, not screenshots). Your proposed stack for this and why. A multi-tenant app you've built and handed over to a client or third party — how you packaged the handover. Confirmation you're comfortable working in my GitHub repo with milestone-based delivery. The word "portal" at the top of your reply so I know you read this.