IEX is the only U.S. stock exchange to publicly provide free market data by web API.

IEX, the Investors Exchange, launched a free, web-based API supplying IEX quoting and trading data for mobile, desktop and trading applications. As America’s newest stock exchange, IEX trades U.S. equity securities, including exchange-traded funds (ETFs).

“IEX is simply providing our Members their own information back to them at no charge,” said Brad Katsuyama, co-founder and CEO of IEX. “The role of an exchange is simple: Members send orders to exchanges and exchanges match orders into trades. Legacy stock exchanges obstruct transparency and create an uneven playing field by overcharging for market data on orders they did not create.”

Accessible via web, IEX API 1.0 provides any individual or academic, public or private institution looking to develop applications that require stock market data to access near real-time quote and trade data for all stocks trading on IEX. For the month of January, IEX matched an average of 128 million shares – equivalent to more than $5 billion of notional value – per day. On a typical day, IEX will trade more than 5,700 different stock symbols.

The IEX API will offer the following data at no cost to users:

1. TOPS aggregates the best bid and offer for all stocks quoted on IEX’s order book, and also provides data for trades on IEX, including price, size and time. For an example of an app that’s using TOPS, see the IEX TOPS viewer app.
2. MARKET tracks industrywide equity trading volume. For an example of an app that’s using MARKET, see the IEX Market volume app.
3. STATS collects aggregate metrics, including volume, notional volume, routed volume and market share. For an example of an app that’s using STATS, see the official IEX mobile app.

No user-specific or identifying data is captured by IEX and none will be made available via IEX API 1.0.

“The relevance of IEX market data increases as our market share grows. So every order sent to IEX is a vote for a different type of stock exchange: one geared towards better trading outcomes, not the sale of data, access and speed,” said Katsuyama.

Launched in September 2016, the Investors Exchange has earned recognition for high execution quality, including the lowest effective spread in more S&P 500 stocks than any other exchange. Technology innovations including IEX’s patent-pending “speed bump” and IEX’s patent-pending Discretionary Peg are designed to deliver the fairest price to investors. IEX operates the only U.S. stock exchange without the conflicts of rebates, co-location and proprietary data revenue streams.

Visit iextrading.com/developer for more details on IEX API 1.0.

Read about our first four months as an exchange on the IEX blog.

About IEX

IEX is the Investors Exchange: a fair, simple, and transparent stock exchange dedicated to investor and issuer protection. Built on the belief that every investor is entitled to the same right to trade on equal terms on every single trade, IEX is on a mission to level the playing field by eliminating unfair advantages from the markets.

On September 2^nd, 2016, IEX launched as America’s newest stock exchange, and regularly matches over 100 million shares daily with a notional value of over $5 billion. On February 21^st, 2017, IEX reached a record market share of 2.3% of total U.S. equity volume. IEX plans to begin listing publicly-traded companies in 2017.