Understanding Market Data and APIs

Getting Started with Market Data

Before building any trading algorithm, you need access to reliable market data. This article covers the most popular data sources and APIs for algorithmic trading.

Popular Data Sources

• Yahoo Finance - Free historical and real-time data
• Alpha Vantage - Professional API with good free tier
• IEX Cloud - High-quality financial data
• Polygon.io - Real-time and historical market data

Code Example

import yfinance as yf
import pandas as pd

# Fetch historical data
ticker = "AAPL"
data = yf.download(ticker, start="2023-01-01", end="2024-01-01")

# Display basic information
print(f"Data shape: {data.shape}")
print(data.head())

Understanding how to access and process market data is fundamental to algorithmic trading success.