![[Chrome for Developers]](https://www.gstatic.com/devrel-devsite/prod/v0f3a5b8b76e4a120372a69044e02756e703b6140f9f1812c6e4a0407b19864b7/chrome/images/lockup.svg){kind=link}
Cross-origin isolation enables a web page to use powerful features such as
SharedArrayBuffer. An extension can opt into cross-origin isolation by
specifying the appropriate values for the cross_origin_embedder_policy and
cross_origin_opener_policy manifest keys. For example, a manifest like the following
will opt the extension's origin into cross-origin isolation.
{
"name": "CrossOriginIsolation example",
"manifest_version": 3,
"version": "1.1",
"cross_origin_embedder_policy": {
"value": "require-corp"
},
"cross_origin_opener_policy": {
"value": "same-origin"
},
...
}
Opting into cross-origin isolation allows the extension to use powerful APIs like SharedArrayBuffers in its cross-origin isolated contexts. However, it does also come with certain side-effects. See Making your website "cross-origin isolated" using COOP and COEP for more information on this.
Caution: Even if an extension opts into cross-origin isolation, not all extension contexts will be cross-origin isolated. For example, cross-origin isolation is not fully implemented for service and shared workers currently. Similarly, a cross-origin isolated extension's web-accessible subframe on a regular web page is not considered cross-origin isolated currently.