Polygon
Financial market data API providing aggregated stock price bars (OHLCV — open, high, low, close, volume) for any US-listed ticker symbol over configurable date ranges and time intervals.
Capability areas
- Aggregate bars — retrieve historical OHLCV data for a stock ticker. Specify the ticker symbol (stocksTicker, e.g. "AAPL"), a date range (start_date, end_date in YYYY-MM-DD), and aggregation window (multiplier + timespan). Timespan values: minute, hour, day, week, month, quarter, year. The multiplier sets how many units per bar (e.g., multiplier=5 + timespan=minute = 5-minute bars). Returns adjusted or unadjusted prices.
Workflows
- Daily price history: fetch daily bars for a ticker over a date range to analyze trends, calculate returns, or build charts.
- Intraday analysis: use minute or hour bars with short date ranges for trading pattern analysis.
- Multi-stock comparison: query aggregate bars for multiple tickers sequentially, then compare performance over the same period.
Gotchas
- Date format: start_date and end_date must be YYYY-MM-DD strings.
- Adjusted prices: set adjusted=true for split/dividend-adjusted prices (recommended for long-term analysis). Defaults to true.
- Sort order: sort=asc (oldest first) or sort=desc (newest first).
- Free tier limits: Polygon's free tier has delayed data (15 min) and limited historical depth. Real-time data requires a paid plan.
- Market hours only: aggregate bars only cover market trading hours unless extended hours are available on the plan.
