Cookies Having Independent Partitioned State (CHIPS) is a Privacy Sandbox proposal that will allow developers to opt a cookie into “partitioned” storage, with separate cookie jars per top-level site.
A partitioned third-party cookie is tied to the top-level site where it’s initially set and cannot be accessed from elsewhere. The aim is to allow cookies to be set by a third-party service, but only read within the context of the top-level site where they were initially set.
The user visits
https://site-2.example, which also embeds
https://3rd-party.example. This new instance of
https://3rd-party.example is still able to access the cookie set when the user was on the previous page.
How It Works Browsers with CHIPs support provide a new attribute for the Set-Cookie HTTP header — Partitioned
Set-Cookie: __Host-example=34d8g; SameSite=None; Secure; Path=/; Partitioned;