# btcdata

Bitcoin data backend service. Fetches BTC prices from Binance (WebSocket) and Kraken (HTTP polling), stores them in PostgreSQL, and exposes a JSON API with Server-Sent Events for live price streaming.

## API

| Endpoint | Description |
|---|---|
| `GET /api/price/stream` | SSE stream — emits `price-update` events with JSON `{price, prev_price, recorded_at}` |
| `GET /api/price/latest` | Latest price as JSON |
| `GET /api/health` | Health check |

## Quick Start

```bash
# Local dev (requires PostgreSQL)
cp .env.example .env   # edit JDBC_URL
make run               # starts on port 4100

# Docker
docker compose up -d   # starts on port 4101
```

## Environment Variables

| Variable | Default | Description |
|---|---|---|
| `BTCDATA_PORT` | `4100` | HTTP server port |
| `JDBC_URL` | — | PostgreSQL connection string |
| `CORS_ORIGIN` | `*` | Allowed origin for CORS headers |

## Data Sources

- **Binance** — WebSocket trade stream (`btcusdt@trade`), throttled to 5s writes
- **Kraken hourly** — OHLC candles polled at HH:01:00 UTC
- **Kraken daily** — OHLC candles polled at 00:01:00 UTC

## Tech Stack

Clojure · Kit · Undertow · Reitit · PostgreSQL · conman · Migratus