The best stock market APIs for developers provide real-time and historical data on stocks, forex, cryptocurrencies, and other financial instruments. These APIs are essential for building algorithmic trading prediction apps, charting stock market data, and analyzing financial trends. The top 7 stock market APIs reviewed include Yahoo Finance API, Alpha Vantage API, Stock and Options Trading Data Provider API, Investing Cryptocurrency Markets API, Zirra API, Twelve Data API, and Finage Currency Data Feed API. Each API has its unique features, popularity scores, latency, success rates, and suitability for specific use cases. The APIs are suitable for developers looking to build financial data-driven applications, including algorithmic trading apps, stock market analysis tools, and cryptocurrency tracking platforms.