Quick answer
The best free stock data API depends on your limit: Alpaca’s free plan gives real-time IEX quotes and history back to 2016 with a free, unfunded account; Twelve Data allows 800 requests a day; Tiingo 1,000 a day with clean adjusted EOD prices; Massive (Polygon) 5 calls a minute with two years of EOD data; Alpha Vantage only 25 a day. Yahoo Finance is free and keyless but unofficial.
Side-by-side comparison
| API | Markets | Auth | Paper / sandbox | Pricing | In AlgoGP |
|---|---|---|---|---|---|
| Alpaca | Stocks, ETFs, Crypto | REST + API key | Paper trading account with simulated fills | Free account; free IEX market data plan | Built into AlgoGP |
| Twelve Data | Stocks, ETFs, Forex, Crypto, Indices | REST + API key | — | Free: 800 requests/day, 8/min | Built into AlgoGP (data)Pro |
| Tiingo | Stocks, ETFs, Crypto, News | REST + API key | — | Free: 50 requests/hour, 1,000/day | Built into AlgoGP (data)Pro |
| Massive (Polygon.io) | Stocks, ETFs, Options, Forex, Crypto, Indices | REST + API key | — | Free: 5 calls/min, end-of-day, 2 years | Built into AlgoGP (data)Pro |
| EODHD | Stocks, ETFs, Forex, Crypto, Fundamentals | REST + API key | — | Free: 20 calls/day; paid from $19.99/mo | Built into AlgoGP (data)Pro |
| Finnhub | Stocks, Forex, Crypto, Fundamentals, News | REST + API key | — | Free tier; paid from $49.99/mo | Built into AlgoGP (data)Pro |
| Alpha Vantage | Stocks, ETFs, Forex, Crypto, Fundamentals | REST + API key | — | Free key: 25 requests/day | Built into AlgoGP (data) |
| Yahoo Finance | Stocks, ETFs, Indices, Futures, Forex, Crypto | Public, no key | — | Free, no key (unofficial) | Built into AlgoGP (data) |
Which one should you pick?
Alpaca if you want free real-time US quotes and long history from one account.
Build with AlpacaTiingo if you need clean, adjusted end-of-day history for many US tickers.
Build with TiingoTwelve Data if you need stocks, FX and crypto from one free key with intraday bars.
Build with Twelve DataEODHD if you need international exchanges on a budget.
Build with EODHDYahoo Finance if you just need quick research data and accept an unofficial source.
Build with Yahoo Finance
Caveats of free data
- Free plans are almost always for personal, non-commercial use.
- Free real-time US data usually comes from one exchange (IEX), not the consolidated SIP feed.
- IEX Cloud, once a favourite free API, shut down in 2024.
Frequently asked questions
What is the best free alternative to Yahoo Finance API?
Tiingo or Twelve Data for official free keys; Alpaca if you also want a broker.
Is there a completely free real-time stock API?
Alpaca’s free plan streams real-time IEX quotes; full consolidated real-time data is paid everywhere.
Test the strategy before you pick the API
Describe your idea to AlgoGP’s copilot, backtest it on years of stock, crypto or forex data with realistic costs, then export Python wired to Alpaca or any built-in broker. Swap the broker later without touching the strategy.
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AlgoGP is not affiliated with any provider listed. Details change; check each provider’s documentation. Nothing here is investment advice.