Alpha Vantage Market Data API
Single function-style REST endpoint that exposes the full Alpha Vantage catalog. Each call includes a function= query parameter (e.g. TIME_SERIES_INTRADAY, GLOBAL_QUOTE, OVERVIEW, INCOME_STATEMENT, RSI, FX_DAILY, CRYPTO_INTRADAY, NEWS_SENTIMENT, REAL_GDP). 20+ years of historical data, free demo key plus paid premium tiers up to 1,200 requests/min.