Cookie blocking

First-party and third-party cookies can be blocked by browser restrictions, user settings, developer flags , or enterprise policy .

User settings

Users can access browser settings to block all on-device site storage, or only third-party cookies.

In Chrome, you can block third-party cookies by selecting the three dots in the upper right corner of your browser window, then selecting Settingson the drop-down menu displayed. Go to Privacy and security> Third-party cookiesand select Block third-party cookies. Alternatively, you can navigate directly to the chrome://settings/cookies page.

You can block local storage of all site data, including cookies, from the On-device site datapage in Google Chrome. Select Settings> Privacy and security> Site settings> Additional content settings> On-device site dataor navigate directly to chrome://settings/content/siteData .

Note that many sites won't function properly if you choose to block all site storage.

The Chrome site data settings page, with 'Don't allow sites to save data on your device (not recommended)' selected

Browser flags

As a developer, the best way to test your site for breakage without third-party cookies in Chrome is to use the test-third-party-cookie-phaseout flag. This flag makes Chrome behave as it does when third-party cookies are restricted, so it's ideal for testing the user experience without cross-site cookies.

The Chrome flags page, with third-party cookie phaseout enabled.

You can enable the test-third-party-cookie-phaseout flag in two ways:

Chrome flags:
Navigate to chrome://flags/#test-third-party-cookie-phaseout and set the flag as Enabled
Command line:
Launch Chrome with the flag --test-third-party-cookie-phaseout

The phaseout flag is available on Windows, macOS, and Linux:

Windows:
chrome.exe --test-third-party-cookie-phaseout
macOS:
open -a Google\ Chrome --args --test-third-party-cookie-phaseout
Linux:
google-chrome --test-third-party-cookie-phaseout

Browser restrictions

To facilitate testing, Google Chrome has restricted third-party cookies by default for 1% of users . If you're in this group, third-party cookies will be limited by default, and your chrome://settings/cookies page will appear as follows.

chrome://settings/cookies page for a browser in the 1% test group
for which cookies are blocked by default — chrome://settings/cookies page for a browser in the 1% test group for which cookies are blocked by default

Other web browsers apply their own cookie policies. For example, Safari has Tracking Prevention , and Firefox has Enhanced Tracking Protection .

Enterprise policy

Cookies may also be blocked by organizational policies set through Chrome Enterprise.

For more information, refer to Chrome Enterprise third-party cookie policies .