Xandr

Formerly a top-tier independent adtech stack; now fully absorbed into Microsoft Advertising as the programmatic infrastructure backbone for Microsoft's ad business.

Xandr, now operating as Microsoft Advertising, was the advertising and analytics subsidiary of Microsoft that ran an online platform for buying and selling consumer-centric digital advertising.¹ Originally formed by AT&T following its acquisition of AppNexus in June 2018, Xandr was built to construct a national TV advertising marketplace and was publicly launched in September 2018.¹ Xandr offered a cross-screen, first-party data-centered demand-side platform (Invest) for advertisers, a sell-side monetization platform (Monetize) for publishers, a self-serve curation platform (Curate) for creating curated marketplaces, and retail media solutions through PromoteIQ, serving advertisers, publishers, content owners, and retailers across digital formats including video.² AT&T sold Xandr to Microsoft in December 2021, with the acquisition completing in June 2022, and in 2023 Microsoft retired the Xandr name and consolidated the business under the Microsoft Advertising brand.¹ Microsoft subsequently closed the demand-side platform, informing clients that it no longer aligned with the company's AI priorities, with support for buying media through Invest ending on February 28, 2026.³ Source 1: wikipedia.org — Xandr Source 2: liveramp.com — Xandr Source 3: digiday.com — Microsoft Advertising is closing the Xandr DSP, layoffs ...