Enable Site Isolation for specified origins

Specify a list of origins that run in a dedicated process.

On Android, this policy only works on devices with sufficient memory (strictly more than 3.2GB RAM), as isolating too many sites on resource-constrained devices may cause performance problems. For resource-constrained Android devices, please use IsolateOriginsShortlist instead.

Devices with less than 1GB memory are not recommended to configure any process isolation specifically.

Each named origin's process will only be allowed to contain documents from that origin and its subdomains. For example, specifying https://a1.example.com/ allows https://a2.a1.example.com/ in the same process, but not https://example.com or https://b.example.com.

Since Google Chrome 77, you can also specify a range of origins to isolate using a wildcard. For example, specifying https://[*.]corp.example.com will give every origin underneath https://corp.example.com its own dedicated process, including https://corp.example.com itself, https://a1.corp.example.com, and https://a2.a1.corp.example.com.

Note that all sites (i.e., scheme plus eTLD+1, such as https://example.com) are already isolated by default on Desktop platforms, as noted in the SitePerProcess policy. This IsolateOrigins policy is useful to isolate specific origins at a finer granularity (e.g., https://a.example.com).

Note that Android isolates certain sensitive sites by default starting in Google Chrome version 77, and this policy extends that mode to isolate specific additional origins.

Also note that origins isolated by this policy will be unable to script other origins in the same site, which is otherwise possible if two same-site documents modify their document.domain values to match. Administrators should confirm this uncommon behavior is not used on an origin before isolating it.

Setting the policy to an empty string or leaving it unset means site isolation won't be required for any specific origins. Users can still turn on process isolation manually, through the command line flag.

Example value: https://a.example.com/,https://othersite.org/,https://[*.]corp.example.com