v144 · miscellaneous

Deprecate and Remove: Related Website Sets (RWS)

Related Website Sets (RWS), formerly known as First Party Sets, provides a framework for developers to declare relationships among sites, to enable limited cross-site cookie access for specific, user-facing purposes. This is facilitated through the use of the Storage Access API (SAA) and requestStorageAccessFor (rSAFor). RWS was designed for use in a browser

concepts

  1. RWS Deprecation Note

    Related Website Sets is being removed. Most multi-origin grouping use cases should switch to a single primary origin plus subdomains under one eTLD+1.

  2. RWS Probe

    Probe document.hasStorageAccess() and surface how cookie blocking re-applies once Related Website Sets is removed.

  3. SSO Migration Architect

    Type your primary + associated origins and your identity provider. The architect builds the right post-RWS stack: collapse to one eTLD+1, FedCM, OAuth/OIDC, per-frame Storage Access — whichever fits each origin.

  4. SSO Without RWS

    A complete walkthrough of cross-subdomain SSO using only standard cookies and requestStorageAccess() — no Related Website Sets needed. Generates the correct Set-Cookie headers for your domains.

why it shipped

Chrome has announced that the current approach to third-party cookies will be maintained. RWS usage is indicated by the number of registered sets (currently at 71 sets), and the usage of the requestStorageAccessFor API (currently at about 0.95% of pageloads), and after this announcement we intend to archive the registration repository, and expect adoption of rSAFor to decrease over time.

references