## Docker Setup

Run the full stack with:

```bash
docker compose up --build
```

Services:

- Frontend: `http://localhost:5173`
- Backend: `http://localhost:4000`
- MongoDB: `mongodb://localhost:27017/chatapp`

The Compose file starts all required services together:

- `frontend` as a Vite container
- `backend` as a Node/Express container
- `mongo` with a persistent `mongo-data` volume

Stop everything with:

```bash
docker compose down
```

Remove containers and database volume with:

```bash
docker compose down -v
```

## Local Development Without Docker

1. Copy the backend environment file:

   ```bash
   cp Backend/.env.example Backend/.env
   ```

2. Start MongoDB locally or with Docker.

3. Start the backend:

   ```bash
   cd Backend && npm run dev
   ```

The backend tries MongoDB at `mongodb://127.0.0.1:27017/chatapp` first and falls back to `Backend/data/db.json` only if MongoDB is unavailable. Use `DATA_STORE=mongo` to fail fast on MongoDB errors, or `DATA_STORE=json` to force the JSON store.