Privacy expectations continue to increase, and major browsers have tightened their rules around third-party cookies. Safari and Firefox already block them by default, and Chrome, while no longer pursuing a full deprecation, has introduced stricter privacy controls.
How does this affect you?
Without third-party cookies to identify them, users are considered new users. In Safari and Firefox — where third‑party cookies cannot be stored at all — this can occur on every pageview. The implications can be significant: An inflated number of users, broken variation stickiness in A/B testing, detached historical data, and more.
To maintain stable user identification, you must serve our DYID cookie from your own server, so it becomes a first-party cookie that isn't affected by these restrictions.
See our Developer Docs to learn how to serve the DYID cookie from your server.
Dynamic Yield by Mastercard Chrome extension
Since 2024, Google has increased restrictions on third-party cookies. If third-party cookies are blocked, several capabilities relating to editing and debugging content on your site won't work. Learn more about how to overcome this restriction with our Chrome extension.