Xandr, formerly known as AppNexus, is an American multinational technology company operating a cloud-based software platform that enables and optimizes programmatic online advertising.
[citation needed] AppNexus offers online auction infrastructure and technology for data management, optimization, financial clearing and support for directly negotiated advertising campaigns.
[2][3] It operates out of multiple data centers, including one in Amsterdam serving Europe and the Middle East, in a facility shared with Equinix.
[6] In October 2019, Xandr purchased Clypd, a privately-held technology company focused on enabling programmatic buying of linear television advertising.
[7] In December 2021, AT&T announced that they had agreed to sell Xandr to Microsoft for an undisclosed price, subject to customary closing conditions, including regulatory reviews.