Google launches Topics API as cookie replacement

In late July 2023, with Chrome 115, Google began making the Privacy Sandbox relevance and measurement APIs — including the Topics API — generally available, targeting about 99% of Chrome users by mid-August 2023 after an origin trial that ended September 20, 2023. The Topics API categorizes a user’s recent browsing into broad interest topics such as Sports or Travel, with processing on the device, and exposes a few topics to sites and ad tech as a privacy-preserving alternative to third-party-cookie interest targeting.

The launch of the Topics API fundamentally disrupts the identity and targeting layer of programmatic advertising, which has historically relied on third-party cookies for cross-site user tracking. For the broader AdTech ecosystem, this creates both challenges and opportunities. Demand-side platforms (DSPs) and data management platforms (DMPs) that built their core value propositions around cookie-based audience segmentation face significant pressure to adapt, as Topics provides far less granular user-level data than cookies historically allowed. This accelerates consolidation pressure among mid-tier identity vendors who lack the scale to build viable alternatives. Competitively, the shift benefits large walled gardens — including Google itself, Meta, and Amazon — that possess vast first-party data ecosystems and are less dependent on third-party cookies for targeting. Critics, including the UK's Competition and Markets Authority (CMA), which had been monitoring Google's Privacy Sandbox commitments, raised concerns that the deprecation of cookies could entrench Google's dominance by disadvantaging independent AdTech players. The CMA's ongoing oversight of the process reflects the regulatory complexity surrounding this transition. The launch also accelerates investment in alternative identity frameworks such as Unified ID 2.0 (The Trade Desk), RampID (LiveRamp), and publisher-side first-party data initiatives. Contextual advertising technology providers stand to benefit as advertisers seek cookie-independent targeting signals. Retail media networks, which operate on first-party purchase and behavioral data, are also positioned as winners in a post-cookie environment. Overall, the Topics API launch reshapes market dynamics by redistributing targeting power toward data-rich platforms and away from the open programmatic ecosystem.