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.
Safari26.5WorksEvery required mapped BCD feature is available without a recorded qualification.
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 WebView150Not supportedAt least one required mapped feature is not available at this browser baseline.
Samsung Internet29.0WorksEvery required mapped BCD feature is available without a recorded qualification.

What this feature can and cannot do

Helps protect against

  • Cross-window reference attacks
  • Cross-origin process isolation gaps

Does not guarantee

  • All cross-origin data exposure
  • Application authorisation
  • Isolation without companion resource policies

What you need before using it

  • Popup and integration compatibility review

Fallback to keep in place

Use defensive opener handling and explicit cross-origin communication checks.