docs: add Development Hosts & Ports section to README

README.md

@@ -273,6 +273,65 @@ Two shortcuts will appear on your desktop:
 
 ---
 
+## 🌐 Development Hosts & Ports
+
+This section defines the default host and port used by each app/service in this turborepo. Update it whenever a new service is added or a port is changed. (Full copy also kept in [docs/ports.md](docs/ports.md).)
+
+### Frontend (React + Vite)
+- **Host:** `localhost` (default) — use `0.0.0.0` if you need LAN access (phone/other device on same Wi-Fi)
+- **Port:** `3000`
+- **Access URLs:**
+  - Local: http://localhost:3000
+  - LAN: `http://<your-ip>:3000` (only if `HOST=0.0.0.0`)
+- **Current setup:** Frontend runs on `0.0.0.0` and is accessible via the device IP.
+
+`.env` file (`apps/Frontend/.env`):
+```env
+NODE_ENV=development
+HOST=0.0.0.0
+PORT=3000
+VITE_API_BASE_URL_BACKEND=http://192.168.1.8:5000
+```
+`VITE_API_BASE_URL_BACKEND` should point at the Backend's `HOST`/`PORT` as seen from the browser — use `localhost` for single-device access, or the machine's LAN IP for access from other devices.
+
+### Backend (Express.js)
+- **Host:** `0.0.0.0` (all interfaces)
+- **Port:** `5000`
+- **Access URL:** http://localhost:5000
+- **Current setup:** Runs for all network interfaces and allows the configured `FRONTEND_URLS` via CORS.
+
+`.env` file (`apps/Backend/.env`):
+```env
+NODE_ENV="development"
+HOST=0.0.0.0
+PORT=5000
+FRONTEND_URLS=http://localhost:3000,http://192.168.1.8:3000
+```
+
+### 🧾 Patient Data Extractor Service
+- **Host:** `localhost`
+- **Port:** `5001`
+- **Access URL:** http://localhost:5001
+
+### 🌐 Selenium Service
+- **Host:** `localhost`
+- **Port:** `5002`
+- **Access URL:** http://localhost:5002
+
+### 💳 Payment OCR Service
+- **Host:** `0.0.0.0`
+- **Port:** `5003`
+- **Access URL:** http://localhost:5003
+
+### 📖 Notes
+- These values come from per-app `.env` files (`apps/<App>/.env`).
+- `HOST` controls binding — `localhost` = loopback only, `0.0.0.0` = all interfaces.
+- `PORT` controls the service's port.
+- Frontend uses variables prefixed with `VITE_` for client-side access (e.g. `VITE_API_BASE_URL_BACKEND`).
+- In production, ports and hosts may differ — traffic is instead routed through the [Cloudflare Tunnel](#cloudflare-tunnel-setup-remote-access-per-office).
+
+---
+
 ## This is a Turborepo. What's inside?
 
 ### Apps and Packages