Origin isolation

Origin isolation allows developers to opt in to giving up certain cross-origin same-site access capabilities — namely synchronous scripting via document.domain, and postMessage()ing WebAssembly.Module instances. This gives the browser more flexibility in implementation technologies. In particular, in Chrome, we will use this as a hint to put the origin in its own process, subject to resource or platform limitations.


Site isolation, i.e. process-per-site, is the current state of the art in protecting websites from each other. Certain legacy features prevent us from aligning this protection boundary with the origin boundary. Origin isolation allows developers to voluntarily give up these legacy features, in exchange for better isolation. Reasons why a site may want better isolation include: performance isolation, allocations of large amounts of memory, side-channel protection (e.g. against Spectre), and improved memory measurement.



Public discussion

Status in Chromium


Origin trial (tracking bug) in:

  • Chrome for desktop release 84
  • Chrome for Android release 84

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • Positive
  • No signal
  • Neutral
  • Positive


Intent to Prototype url

Intent to Prototype thread

Last updated on 2020-10-25