Finnhub
Financial data API providing real-time stock quotes, fundamental data, earnings, news, and alternative data (insider trading, ESG scores) via REST and WebSocket, with a generous free tier.
79
NASDAQ Data Link (formerly Quandl)
Financial and economic dataset API (rebranded from Quandl to NASDAQ Data Link) providing access to hundreds of curated datasets including commodities, macro indicators, and alternative financial data.
71
Alpha Vantage
Free and premium REST API for real-time and historical stock prices, forex rates, cryptocurrency data, and technical indicators, widely used for financial analysis and trading applications.
63