Xandr

Was a top-tier independent programmatic platform competing in the open internet advertising ecosystem before being absorbed into Microsoft Advertising

Xandr was an advanced advertising technology platform originally launched by AT&T in 2018, built upon the foundation of AppNexus, which AT&T acquired for approximately $1.6 billion in 2018. The platform brought together premium video and display inventory, data-driven targeting capabilities, and a full suite of programmatic tools including a demand-side platform (DSP), supply-side platform (SSP), and data marketplace. Xandr positioned itself as a premium alternative to the dominant walled gardens, leveraging AT&T's vast first-party data assets from its media and telecommunications properties to offer advertisers and publishers more precise, privacy-conscious audience targeting at scale. In December 2021, Microsoft acquired Xandr from AT&T, integrating its technology into Microsoft's growing advertising business. Following the acquisition, Microsoft systematically retired the Xandr brand and consolidated its products under the Microsoft Advertising umbrella. The Xandr DSP was rebranded as Microsoft Invest, the SSP became Microsoft Monetize (completed May 2024), and Curate became Microsoft Curate. Microsoft Invest is scheduled for sunset on February 28, 2026, as Microsoft continues to evolve its advertising technology stack. During its operational years, Xandr was a significant force in the open programmatic ecosystem, competing with The Trade Desk, Google's DV360, and Amazon DSP. Its Invest DSP and Monetize SSP served enterprise advertisers, agencies, and premium publishers globally, and its Curate product enabled media companies to package and sell audience segments programmatically. The Xandr brand has since been fully retired, with its legacy living on through the Microsoft Advertising platform.