Support in current browsers

Checked against the current browser versions recorded in MDN browser data 8.0.7.

BrowserMinimumOutcomeReason
Chrome150WorksEvery required mapped BCD feature is available without a recorded qualification.
Edge150WorksEvery required mapped BCD feature is available without a recorded qualification.
Firefox152WorksEvery required mapped BCD feature is available without a recorded qualification.
Safari26.5Works with limitsEvery required mapped feature is available, but BCD records one or more qualifications.
Chrome for Android150WorksEvery required mapped BCD feature is available without a recorded qualification.
Firefox for Android152WorksEvery required mapped BCD feature is available without a recorded qualification.
Safari on iOS26.5WorksEvery required mapped BCD feature is available without a recorded qualification.
Android WebView150WorksEvery required mapped BCD feature is available without a recorded qualification.
Samsung Internet29.0WorksEvery required mapped BCD feature is available without a recorded qualification.

What this feature can and cannot do

Helps protect against

  • Cross-site request forgery
  • Unnecessary cross-site cookie exposure

Does not guarantee

  • Same-site request forgery
  • Cross-site scripting
  • Authentication and authorisation design

What you need before using it

  • Explicit cookie classification
  • Secure transport for SameSite=None

Fallback to keep in place

Use CSRF tokens, origin validation, Secure cookies, and ordinary authorisation checks.