PSA: Third-party cookie deprecation for 1% of Chrome Stable starting Q1 2024

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Rowan Merewood

May 22, 2023, 10:47:21 AM5/22/23
to blink-dev
Hi blink-dev,

As an FYI, here are the key points distilled for readers of this list:

- We are planning to provide two modes of Chrome-facilitated testing for sites to meaningfully preview working in a world without third-party cookies. We will send I2Ps for each of these.

Mode A: Ad techs can receive control and experiment labels on a portion of traffic and use these to conduct testing and experiments starting in Q4 2023.

Mode B: Chrome globally disables third-party cookies for up to 1% of all Chrome users starting in Q1 2024.

Note that Mode B will apply to all third-party cookies in that 1% population, and may impact user-facing functionality. If your sites rely on third-party cookie data, then we have a guide for understanding if CHIPS or First-Party Sets address your needs: and an issue tracker for reporting affected sites:

- We'll be sending the I2S messages for Topics, Protected Audience, Attribution Reporting, Private Aggregation, Shared Storage, Fenced Frames soon targeting 115.

- We've got open issues on the Chrome-facilitated testing options here: and you can also raise additional questions there.
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