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This means that from the start of 2024, you can expect to see an increased portion of Chrome users on your site
with third-party cookies disabled even if you are not actively participating in the Chrome-facilitated testing. This
testing period continues through to Q3 2024 when, after consultation with the CMA and subject to resolving any
competition concerns, we plan to begin disabling third-party cookies for all Chrome users.

Prepare for the third-party cookie phase out

We've broken the process down into these key steps, with detail below, to ensure you're prepared for your site to
run without third-party cookies:

1. Audit your third-party cookie usage.

2. Test for breakage.

3. For cross-site cookies which store data on a per site basis, like an embed, consider Partitioned with
CHIPS.

4. For cross-site cookies across a small group of meaningfully linked sites, consider Related Website Sets.

5. For other third-party cookie use cases, migrate to the relevant web APIs.

1. Audit your third-party cookie usage

Third-party cookies can be identified by their SameSite=None value. You should search your code to look for
instances where you set the SameSite attribute to this value. If you previously made changes to
add SameSite=None to your cookies around 2020, then those changes may provide a good starting point.

Chrome DevTools

The Chrome DevTools Network panel shows cookies set and sent on requests. In the Application panel you can
see the Cookies heading under Storage. You can browse the cookies stored for each site accessed as part of the
page load. You can sort by the SameSite column to group all the None cookies.