Cross-origin isolation
Cross-origin isolation is a browser state enabled by compatible opener and embedder policies. It allows capabilities such as shared memory in supported contexts.
What it is
Cross-origin isolation is a browser state enabled by compatible opener and embedder policies. It allows capabilities such as shared memory in supported contexts.
Why it matters
It is a page-wide resource-loading contract, not merely a switch for faster inference.
Example
A page can use COOP: same-origin and COEP: require-corp, then check crossOriginIsolated before enabling threaded WASM.
Technical detail
Cross-origin subresources may need CORS or a suitable Cross-Origin-Resource-Policy header to load under COEP.
When to use it
Provide a single-thread fallback and inspect blocked fonts, images, and scripts after enabling isolation.
Sources
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Assembled from the ReLU.chat curated knowledge base. These explanations are concise on purpose; check the sources for anything important.