Alpaca's Trading API runs on https://paper-api.alpaca.markets/v2 for paper trading and https://api.alpaca.markets/v2 for live. Market data comes from https://data.alpaca.markets.
Generate a key pair on the Alpaca dashboard and send them as APCA-API-KEY-ID and APCA-API-SECRET-KEY headers. In the examples they're written {{ALPACA_KEY_ID}} and {{ALPACA_SECRET_KEY}}.
Full reference: https://docs.alpaca.markets/
Buying power, cash, equity.
curl https://paper-api.alpaca.markets/v2/account \
-H "APCA-API-KEY-ID: {{ALPACA_KEY_ID}}" \
-H "APCA-API-SECRET-KEY: {{ALPACA_SECRET_KEY}}"
curl -X POST https://paper-api.alpaca.markets/v2/orders \
-H "APCA-API-KEY-ID: {{ALPACA_KEY_ID}}" \
-H "APCA-API-SECRET-KEY: {{ALPACA_SECRET_KEY}}" \
-H "Content-Type: application/json" \
-d '{"symbol": "AAPL", "qty": "1", "side": "buy", "type": "market", "time_in_force": "day"}'
curl "https://data.alpaca.markets/v2/stocks/AAPL/bars?timeframe=1Day&limit=5" \
-H "APCA-API-KEY-ID: {{ALPACA_KEY_ID}}" \
-H "APCA-API-SECRET-KEY: {{ALPACA_SECRET_KEY}}"