Stockdata.dev – Free stock market API with 15-min delayed US quotes
Parses messy SEC XBRL into a simple REST surface — income statements, balance sheets, cash flow, filings with direct EDGAR links, plus insider trades and 13F holdings. The docs are clear (curl examples, param details, sample JSON) and the free 1,000-call tier makes it easy to prototype. Missing clarity on coverage, update cadence, and paid-tier limits keeps this from feeling like a must-have API for production at scale.