AppNexus is a New York City-based company that provides a platform specializing in real-time online advertising. As of 2010, the company auctions more than four billion ads per day on a real-time basis.

AppNexus offers online auction

Online auction business model

The online auction business model is one in which participants bid for products and services over the Internet. The functionality of buying and selling in an auction format is made possible through auction software which regulates the various processes involved.Several types of online auctions are...

 infrastructure and technology for data management, optimization, financial clearing and support for directly negotiated advertising campaign

Advertising campaign

An advertising campaign is a series of advertisement messages that share a single idea and theme which make up an integrated marketing communication...

s. It integrates with advertising sources including Google's DoubleClick

DoubleClick

DoubleClick is a subsidiary of Google that develops and provides Internet ad serving services. Its clients include agencies, marketers and publishers who serve customers like Microsoft, General Motors, Coca-Cola, Motorola, L'Oréal, Palm, Inc., Apple Inc., Visa USA, Nike, Carlsberg among others...

, Microsoft's AdECN, and aggregators. It operates out of multiple data center

Data center

A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems...

s, including one in Amsterdam

Amsterdam

Amsterdam is the largest city and the capital of the Netherlands. The current position of Amsterdam as capital city of the Kingdom of the Netherlands is governed by the constitution of August 24, 1815 and its successors. Amsterdam has a population of 783,364 within city limits, an urban population...

 serving Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and the Middle East

Middle East

The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...

, in a facility shared with Equinix

Equinix

Equinix, Inc. is an American public corporation that provides carrier-neutral data centers and internet exchanges. Equinix provides network-neutral data centers and interconnection services...

.

Founders and financing

AppNexus was founded by Brian O'Kelley (the ex-CTO of Right Media

Right Media

Right Media, Inc. is an online advertising company that operates the Right Media Exchange , a marketplace that enables advertisers, publishers, and ad networks to trade digital media. Technology providers develop services for the Exchange via APIs....

) and Mike Nolet (former product manager and Director of Analytics at Right Media); Michael Rubenstein, a former VP and General Manager at Google's DoubleClick

DoubleClick

DoubleClick is a subsidiary of Google that develops and provides Internet ad serving services. Its clients include agencies, marketers and publishers who serve customers like Microsoft, General Motors, Coca-Cola, Motorola, L'Oréal, Palm, Inc., Apple Inc., Visa USA, Nike, Carlsberg among others...

, joined AppNexus as President in September 2009. The company is financially backed by Microsoft

Microsoft

Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

, Khosla Ventures

Khosla Ventures

Khosla Ventures is a venture capital firm focused on early stage companies in the Internet, computing, mobile, silicon technology and clean technology sectors....

, First Round Capital

First Round Capital

First Round Capital is a venture capital firm that specializes in providing seed-stage funding to technology companies. Managed by Josh Kopelman, Chris Fralic, Rob Hayes and Howard L. Morgan, the Philadelphia-based company typically provides seed-stage investment that ranges from $250,000 to $500,000...

, Venrock, Kodiak Venture Partners, Marc Andreessen

Marc Andreessen

Marc Andreessen is an American entrepreneur, investor, software engineer, and multi-millionaire best known as co-author of Mosaic, the first widely-used web browser, and co-founder of Netscape Communications Corporation. He founded and later sold the software company Opsware to Hewlett-Packard...

, Ben Horowitz

Ben Horowitz

Ben Horowitz is a high technology entrepreneur and investor. He is best known for co-founding and running the enterprise software company Opsware. In July 2007, Horowitz sold Opsware to Hewlett-Packard for $1.6 billion in cash...

, and Ron Conway

Ron Conway

Ron Conway is an American angel investor, often described as one of the "super angels". Conway is recognized as a strong networker and is based in Silicon Valley.-Early career:...

; as of October 2010 the company has raised over $65 million in financing.