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Prepare for phasing out third-party cookies Related Website Sets Related Website Sets: developer guide How Chrome evolved the First-Party Sets proposal Cookies Having Independent Partitioned State (CHIPS) Storage Partitioning Fenced frames
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Shared Storage Shared Storage API walkthrough
IP Protection Privacy Budget Bounce tracking mitigations
User-Agent reduction User-Agent reduction snippets
Topics API overview Topic classification Developer guide Integration guide Experiment and participate Topics API demos Test topic inference in a colab Topics API latest updates
Protected Audience API Experiment and participate
Protected Audience API: developer guide Seller guide: run ad auctions Buyer guide: join interest groups and generate bids Protected Audience API auction reporting Sequential auction setup with header bidding and multi-seller Protected Audience auction Improve Protected Audience API auction latency Opt-out of the Protected Audience API Report on Protected Audience API auction results Troubleshoot the Protected Audience API
Status of pending Protected Audience API capabilities Protected Audience API walkthrough
Content selection with Shared Storage Creative rotation Creative selection by frequency A/B Testing Known customers
Maximize ad relevance
Attribution Reporting overview Attribution Reporting end-to-end Experiment and participate Why Chrome plans to ship the Attribution Reporting API
Introduction to debug reports Set up debug reports Debugging cookbook
Attribution Reporting API developer guide Get started with Attribution Reporting Register attribution sources Register attribution triggers Prioritize specific clicks, views, or conversions Define custom rules using filters Prevent duplication in reports Custom report windows Register multiple reporters Report schedules Constraints on Aggregation Reporting data Web-to-app and app-to-web measurement Understanding aggregation keys Understanding noise in summary reports Working with noise Contribution budget for summary reports
API updates
Private Aggregation API Private Aggregation API fundamentals Experiment and participate Unique reach measurement User demographic reporting K+ frequency measurement
Aggregation Service Summary reports
Private State Tokens

Related Website Sets

Related Website Sets (RWS) is a way for a company to declare relationships among sites, so that browsers allow limited third-party cookie access for specific purposes.

Published on • Updated on

Milica Mihajlija
Milica Mihajlija

Milica is a technical writer at Chrome.

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Update

First-Party Sets has been renamed to Related Website Sets. To learn more about the name change, refer to the blog post.

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, example.co.uk and so on.

Diagram showing brandx.com, fly-brandx.com and drive-brandx.com as one group and example.com, example.rs, example.co.uk as another group.

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 blocking third-party cookies to improve privacy on the web, new mechanisms are needed to enable these experiences to work.

Cookies set by the site you visit—the one shown in the URL bar—are first-party cookies. A site you visit can embed content from other sites: for example, images, ads, and text. Cookies coming from sites other than the current site are third-party cookies.

Related Website Sets is a way for a company to declare relationships among sites, so that browsers allow limited third-party cookie access 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 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

Updated on • Improve article

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