Real time data here are two that are free: https://www.alphavantage.co/documentation/ https://www.alphavantage.co/documentation/ https://iextrading.com/develo

Real time data here are two that are free: https://www.alphavantage.co/documentation/ https://www.alphavantage.co/documentation/ https://iextrading.com/developer/docs/#getting-started https://iextrading.com/developer/docs/#getting-started The majority of discount stock brokers provide API, here is one example: https://www.interactivebrokers.com/en/index.php?f=5041 https://www.interactivebrokers.com/en/index.php?f=5041 Historical data, the cheapest I can find 20+ years of data fro less than a $100 was on eBay, just search for: "us historical stock market data"