Xandr

Formerly a leading independent end-to-end programmatic platform; absorbed into Microsoft Advertising as of 2023, with its products rebranded under the Microsoft Advertising suite.

Xandr was an advertising technology company originally formed when AT&T acquired AppNexus in 2018 and rebranded it as Xandr, combining AppNexus's powerful programmatic infrastructure with AT&T's vast first-party data assets. The platform offered a comprehensive suite of AdTech tools including a demand-side platform (DSP), supply-side platform (SSP), data marketplace, and curation capabilities, positioning itself as a premium end-to-end solution for advertisers, publishers, and data providers in the digital advertising ecosystem. Microsoft acquired Xandr from AT&T in 2022, gaining a sophisticated programmatic advertising stack to bolster its Microsoft Advertising offerings. Following the Microsoft acquisition, the Xandr brand was progressively retired throughout 2023 and into 2024 as its constituent products were absorbed into the Microsoft Advertising umbrella. The DSP was rebranded as Microsoft Invest (with a planned sunset on February 28, 2026), the SSP became Microsoft Monetize (rebranded May 2024), and the curation product became Microsoft Curate. Xandr's technology and infrastructure formed the backbone of Microsoft's expanded programmatic advertising capabilities, giving Microsoft a competitive position against Google's DV360/GAM stack and The Trade Desk in the open internet advertising market. At its peak, Xandr was recognized as one of the most sophisticated independent AdTech platforms, known for its robust APIs, transparent marketplace model, and strong publisher relationships. Its legacy lives on through the Microsoft Advertising platform, which inherited Xandr's technology, talent, and publisher supply relationships, making Microsoft a more formidable player in the global programmatic advertising landscape.