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Cookie Partitioning

Tracking

Tracking Third‑Party Cookies First‑Party Isolation Storage Partitioning

Browser privacy feature partitioning third-party state by top-level site to reduce cross-site correlation.

Definition

Cookie partitioning isolates third-party cookie storage per top-level site (often along with other storage). This reduces the ability of third parties to track users across sites via shared identifiers.

In plain English Browser privacy feature partitioning third-party state by top-level site to reduce cross-site correlation.

Why this matters

Why it matters: Cross-site identifiers power profiling; partitioning shrinks linkability for trackers.

Example

Example: A third-party analytics cookie is partitioned so it differs per site, limiting correlation across domains.