MediHealth AI

AI-powered medication safety assistant — React Native (Expo) app with a Cloudflare Worker AI proxy, Appwrite for auth and data, and NVIDIA NIM (StepFun 3.7 Flash) for analysis.

Architecture

Expo app (client/)  ──HTTPS──►  Cloudflare Worker (worker/)  ──►  NVIDIA NIM API
       │                            holds NIM key as a secret
       └──────Appwrite SDK (auth, database)──────►  Appwrite Cloud

The NVIDIA API key lives only in the Worker as a Cloudflare secret. It is never compiled into the app bundle (EXPO_PUBLIC_* variables are inlined into the APK and readable by anyone who unzips it — don't put keys there).

server/ contains a fully-written Express API (including an OpenFDA / MedlinePlus / Drugs.com verification service). It is not currently wired into the mobile app — the client talks to Appwrite and the Worker directly. It is kept for a planned source-verification feature.

Stack

Layer	Technology
Mobile	React Native, Expo 53, Expo Router, React Query
AI proxy	Cloudflare Workers (free tier)
AI	NVIDIA NIM — nvidia/nemotron-3-nano-omni-30b-a3b-reasoning
Database & Auth	Appwrite

Quick Start

1. Deploy the AI proxy (~10 min, free)

Follow worker/README.md:

cd worker
npm install
npx wrangler login
npx wrangler secret put NIM_API_KEY   # paste your nvapi-... key from build.nvidia.com
npx wrangler deploy

2. Mobile App

cd client
npm install
cp .env.example .env
# set EXPO_PUBLIC_AI_PROXY_URL to the wrangler deploy URL
npx expo start

3. Demo Account

Field	Value
Email	demo@medihealth.app
Password	Demo123!

Tap Enter Demo on the login screen.

Features

• AI medication analysis — interactions, side effects, food interactions, safety score with explicit "not assessed" state (no invented scores)
• AI Vision medication scanner (photo → extract medications → analyze)
• Medication library with search, forms, date ranges, edit & delete
• Smart reminders with local notifications and dose taken/skipped logging
• Analysis & scan history with severity filters
• Arabic (default, full RTL) + English
• Light/dark/system themes

Source verification against official drug labels (OpenFDA, MedlinePlus, Drugs.com) is implemented in server/src/services/webResearch.service.ts but not yet reachable from the app — the analysis screen labels results as "AI-generated / unverified" until that ships.

Project Structure

MediHealth/
├── client/           # Expo React Native app
│   ├── app/          # Expo Router screens
│   └── src/          # Components, theme, contexts, services
├── worker/           # Cloudflare Worker — AI proxy (holds the NIM key)
├── server/           # Express API — written but not wired into the app yet
└── docs/             # Database schema

Environment Variables

• client/.env.example — app-side config (EXPO_PUBLIC_AI_PROXY_URL, optional shared secret)
• worker/ secrets — NIM_API_KEY (required), APP_SHARED_SECRET (optional)

Never commit .env, .dev.vars, or keystores. Anything prefixed EXPO_PUBLIC_ ships inside the APK.

Database (Appwrite Collections)

• user_profiles — fullName, email, preferredLanguage
• user_medications — user medications
• reminders / reminder_completions
• analysis_reports — AI analysis history
• scan_histories — vision scan history

Security

• NVIDIA key stored as a Cloudflare Worker secret, never in the app bundle
• Worker exposes only two constrained routes (/analyze, /extract) — no general chat passthrough; NVIDIA's ~40 RPM free-tier limit caps abuse
• *.keystore / *.jks gitignored; Android release-signing passwords read from ~/.gradle/gradle.properties or env vars, not committed
• Appwrite handles auth and password hashing

License

MIT License