Maybe there is some program that will provide a snapshot at any point in time where the output could be parsed...It seems that brokerage houses make customers pay for real-time market updates. How is this different? I suspect that any market data that is in real-time will be fee based.
curl "https://api.nbp.pl/api/exchangerates/rates/A/USD/?format=json" :-{"table":"A","currency":"funt szterling","code":"GBP","rates":[{"no":"084/A/NBP/2026","effectiveDate":"2026-05-04","mid":4.9229}
If only it was command line and you could enter the currencies you were interested in.