Cross‑Origin Opener Policy (COOP)
Response header that isolates a browsing context from cross‑origin windows, mitigating cross‑origin side‑channel risks.
#web#security#headers
Last updated: 2025-09-07T00:00:00.000Z
Evidence
OTHER HTML Standard — Cross‑Origin Opener Policy Normative evidence
More context
COOP enforces process isolation for top‑level documents using values like same‑origin to reduce interference.