The REST grammar
Each request names an instrument, a resolution and a window, and returns up to 5,000 rows. Longer ranges page through with the same key. A call like client.candles("BTC/USD", "1d", start="2026-01-01") returns a dataframe ready for pandas or a backtest. Beyond candles, the same grammar serves the economic calendar, insider trades, dividends, stock splits and company profiles. The full reference lives at /docs/api.
The live WebSocket
One connection streams every covered asset class together, so a portfolio of stocks and currency pairs does not need two integrations. The free key streams 16 symbols at a time. The feed can replay recorded history and then switch to live data on the same connection, so the strategy code does not change between the backtest and the live session. The protocol is documented at /docs/websocket.
Coverage
| Asset class | Instruments | Notes |
|---|---|---|
| Stocks | 3,987 | US and international listings |
| Forex | 62 pairs | G10 majors, crosses and exotics |
| Crypto | 58 | Major tokens and trading pairs |
| ETFs | 25 | Index and sector funds |
| Commodities | 23 | Metals and energy |
| Indices | 13 | Major global benchmarks |
Daily candles reach back to 2003 on long listed instruments. Comparable commercial candle APIs price the same grammar at $50 to $200 per month and meter it per call. This API is free within a shared monthly allowance, with no tiers to manage.
Updated 11 June 2026.
