Tools

Market data APIs for stocks, options, futures, forex, and crypto, from the company formerly known as Polygon.io. REST and WebSocket endpoints cover historical bars through tick data, and existing Polygon keys keep working during the rebrand.

Best forDevelopers who want one vendor for US market data across several asset classes, including people replacing IEX Cloud.

Historical and realtime bars, quotes, and trades for US stocks, options, and crypto. It pairs with the Alpaca trading API or can be used on its own.

Best forBuilding research notebooks or live monitors next to an Alpaca brokerage account.

End-of-day prices, fundamentals, news, crypto, and forex through a REST API. A practical low-cost feed for research after IEX Cloud shut down.

Best forPersonal research projects that need clean daily US equity history plus news.

REST API for stock, forex, and crypto prices, plus technical indicators, fundamentals, and options data. The free key is enough to prototype and tight enough that production systems usually move to a paid plan.

Best forFirst prototypes and indicator experiments before you commit to a market-data vendor.

Normalized historical and live market data down to trades and order-book detail, aimed at quantitative research. Coverage is centered on US equities, options, and futures venues.

Best forTick and order-book research where a typical end-of-day API is too coarse.

REST API for quotes, company fundamentals, estimates, filings, and news across stocks, forex, and crypto. A free tier covers light use.

Best forAdding fundamentals and news next to a price feed without standing up several vendors.

REST and WebSocket market data for stocks, forex, ETFs, and crypto across many countries, including technical-indicator endpoints. A common replacement path after IEX Cloud shut down.

Best forApps that need global symbols and a straightforward time-series API.

Nasdaq's dataset platform, formerly Quandl, for economic, alternative, and financial tables through REST, Python, and related access tools. Some datasets are free to query and many are paid.

Best forPulling curated alternative and economic datasets into a research pipeline.

End-of-day and intraday prices plus fundamentals for equities, ETFs, forex, and crypto on a long list of exchanges. Built for bulk history more than for colocated trading.

Best forGlobal end-of-day research when US-only vendors leave gaps.

REST API for financial statements, ratios, prices, and related company data. Useful when a strategy needs fundamentals more than tick history.

Best forScreening and fundamental features in Python or a spreadsheet-style backend.

Paid market data and fundamentals platform aimed at business and institutional integrations, including equities and options products. The docs cover a versioned REST API.

Best forTeams that need a vendor contract and support rather than a hobby-tier key.

Federal Reserve Bank of St. Louis API for economic time series such as rates, inflation, and employment. The data is free and widely used as a macro input.

Best forAdding official macro series to an equity or rates study.

Crypto prices, market cap, volume, and exchange data through a documented REST API. A free demo tier exists alongside paid plans.

Best forCrypto universe screens and portfolio marks that do not need exchange-grade ticks.

Cryptocurrency market data API for prices, rankings, and exchange metadata. A free key is available with rate limits.

Best forA second crypto reference feed when you want rankings and metadata beside exchange prices.

Community library that speaks to many crypto exchanges through one API for public market data and, where supported, private trading. It is not an official client of any single exchange.

Best forResearch or execution code that should move between crypto exchanges without a rewrite.

Community Python library that downloads Yahoo Finance prices, fundamentals, and option chains. Yahoo does not publish this library as an official API, and the endpoints it uses can change.

Best forQuick historical studies and teaching examples, not a production data license.

Commission-free brokerage API for US stocks, options, and crypto, with a paper-trading environment and WebSocket updates. A common first live broker for Python trading systems.

Best forGoing from a paper account to live US stock, options, or crypto orders with a modern REST API.

TWS API and Client Portal Web API for global stocks, options, futures, forex, and bonds. API access comes with an IBKR account. Some market-data subscriptions are paid separately.

Best forMulti-asset execution when one broker needs to cover more than US stocks.

REST API for brokerage accounts, market data, and orders, with a sandbox and WebSocket quotes. Oriented toward US stocks and options.

Best forOptions-aware US equity apps that want a documented sandbox before live orders.

REST API for TradeStation accounts and orders across stocks, options, futures, and crypto. The platform also includes EasyLanguage for automated strategies.

Best forFutures and multi-asset automation on an established US brokerage platform.