cookieless-alternatives
Cookie-less Tracking Alternatives
Overview
The deprecation of third-party cookies by browsers and increasing consent-driven restrictions on first-party cookies are driving the advertising and analytics industries toward alternative measurement and targeting approaches. Google's Privacy Sandbox initiative, launched in 2019 and iteratively developed through 2024-2026, provides a suite of browser APIs designed to replace cross-site tracking functionality with privacy-preserving alternatives. Alongside browser-based solutions, server-side analytics and probabilistic measurement methods offer additional paths. This skill evaluates each alternative's privacy properties, technical requirements, and readiness for production use.
Privacy Sandbox APIs
Topics API
Purpose: Interest-based advertising without cross-site tracking.
How It Works:
- Chrome observes the user's browsing activity (top-level page visits) locally on-device
- Each week, the browser classifies visited sites into topics from a taxonomy of approximately 470 advertising-relevant categories
- When an ad tech company calls the Topics API on a publisher's site, the browser returns up to 3 topics (one from each of the last 3 weeks)
- Topics are selected with 5% random noise (a random topic is returned instead of the true one)
- A caller only receives topics that it has also observed the user being interested in (on other sites where the caller was present)