REST Polling vs WebSockets for Market Data
REST polling vs WebSockets for market data: the message rate math your consumer must keep up with, and the recovery path when a socket drops mid session.
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Stock Correlation Matrix in One SQL Query
A stock correlation matrix in one SQL query over daily returns, plus the curl and jq version and the measurement mistakes that quietly inflate the numbers.
Do NYSE and Nasdaq Have Public APIs?
Do NYSE and Nasdaq have public APIs? What each exchange really publishes, who can access real time quotes, what it costs, and the license rules behind it.
Free Stock API With curl and jq: No Key
Call a free stock market API from the shell: install curl and jq on Ubuntu, read the JSON, filter rows with jq, and export clean CSV. No key needed.
Free Stock Market Data API, No Key Required
A free stock market data API with no key and no signup: seven curated JSON queries over US equities and options, cached at the edge and open to AI agents.
Free SQL API for Stock Market Data
A free SQL API for stock market data: write real SQL against 22 years of US equities, dividends, and fundamentals. 100 queries a day, no credit card.