Project overview, setup instructions, and architecture summary for the PayBack medical bill analysis and dispute flow.

• frontend/ — React/Vite app: upload bills, view decoded results and flags, build and send dispute emails.
• backend/ — FastAPI app: bill upload, Gemini extraction & analysis, ORIA benchmarks, rules engine, case building, MongoDB persistence.

• Node.js 18+ (for frontend)
• Python 3.11+ (for backend)
• MongoDB (local or Atlas URI)
• Gemini API key (for bill extraction/analysis)
• Optional (backend): Poppler installed on the system for pdf2image (PDF → images). On Windows you may need to install it (e.g. via conda or poppler-windows); on macOS: brew install poppler. If python-magic fails on Windows, try pip install python-magic-bin instead.

1. Clone and env

   • Copy .env.example → .env in project root.
   • Copy frontend/.env.example → frontend/.env.
   • Fill in MONGODB_URI, GEMINI_API_KEY; set VITE_API_BASE_URL=http://localhost:8000 in frontend/.env.

2. Backend

   cd backend && pip install -r requirements.txt && uvicorn main:app --reload

   • API runs at http://localhost:8000. Check http://localhost:8000/health.

3. Frontend

   cd frontend && npm install && npm run dev

   • App runs at http://localhost:5173.

4. Docs for teammates

   • DesignDoc.md (frontend) — UI/UX and design system.
   • Project Structure.md — file layout and responsibilities.

Upload → PDF/image conversion → Gemini extraction → ORIA/hospital matching & rules engine → flagged charges → case builder → dispute letter prompt → email formatter. Bills and cases stored in MongoDB. Users open an email draft or copy to clipboard.

• Backend: FastAPI app runs with CORS and /health; service modules and routes are stubs — implement in backend/main.py and backend/services/.
• Frontend: React app mounts with routes (/, /results/:billId, /dispute/:caseId); pages and components are stubs — implement per frontend/DesignDoc.md.
• API client: frontend/src/api/client.js — uploadBill, getAnalysisResult, getPrecedents, searchPrecedents, etc. using VITE_API_BASE_URL.