Related Website Sets (RWS) is a way for a company to declare relationships among sites, so that browsers allow limited cross-site data access for specific purposes.
Many organizations have related sites with different domain names, such as
brandx.com and fly-brandx.com—or domains for different countries such as
example.com, example.rs, and example.co.uk.
Imagine a company that helps you book a vacation. The company has two related
sites: fly-brandx.com and drive-brandx.com to separate flights and car hire.
Over the course of booking one journey, you can go between these sites to select
their different options and you'd expect your shopping cart to remember your
choices across these sites.
Related sites like these often rely on cookies to keep you signed in or show you personalized content.
As Chrome moves towards making third-party cookies obsolete to improve privacy on the web, new mechanisms are needed to enable these experiences to work.
Define related sites with Related Website Sets
Related Website Sets is a way for a company to declare relationships among sites, so that browsers allow limited access to cross-site data, such as third-party cookies, for specific purposes. Chrome will use these declared relationships to decide when to allow or deny a site access to their cookies when in a third-party context.
At a high level, a Related Website Set is a collection of domains, for which there is a single "set primary" and potentially multiple "set members."
Site authors need to submit their domains to a set. Set members can include a range of different domain types with subsets based on use cases.
Related Website Sets use cases
Related Website Sets are a good match for cases when an organization needs a form of shared identity across different top-level sites. Shared identity in this case means anything from a full single sign-on solution to just needing a shared preference across sites.
An organization may have different top-level domains for:
- Branded domains:
fly-brandx.com, drive-brandx.com - App domains:
calendar-brandx.com, mail-brandx.com - Country-specific domains to enable localization:
brandx.co.uk,brandx.rs - Service domains that users never directly interact with, but provide
services across the same organization's sites:
brandx-assets.com - Sandbox domains that users never directly interact with, but exist for
security reasons:
brandx-usercontent.com
Find out more
- First-Party developer guide
- Related Website Sets technical explainer
- Chrome Platform Status
- Chromium Projects
- Privacy Sandbox Developer Support repo
- Create an issue on the proposal repository for questions about the proposal.