# btcprice

Bitcoin price tracker UI. Serves an HTML page with live price updates streamed from [btcdata](../btcdata) via WebSocket using HTMX.

## Quick Start

```bash
# Start btcdata first (provides price data)
cd ../btcdata && make run

# Local dev
make run       # starts on port 4000
make tailwind  # watch Tailwind CSS (separate terminal)

# Docker (starts both btcprice + btcdata)
docker compose up -d   # btcprice on 4041, btcdata on 4101
```

## Environment Variables

| Variable | Default | Description |
|---|---|---|
| `PORT` | `4000` | HTTP server port |
| `BTCDATA_URL` | `http://192.168.50.42:4100` | btcdata service URL (browser connects via WebSocket) |

## How It Works

The server renders an HTML page with HTMX and the WebSocket extension (`hx-ext="ws"`). HTMX connects directly to btcdata's WebSocket endpoint (`BTCDATA_URL/api/price/ws`), which sends HTML fragments. HTMX swaps the received `<div id="price-display">` into the DOM automatically. Price changes are color-coded (green up, red down). Reconnection is handled by HTMX with exponential backoff.

## Tech Stack

Clojure · Kit · Undertow · Reitit · Hiccup · HTMX · Tailwind CSS v4