This is a proposal for enabling seamless navigations between sites or pages. In particular, this proposal enables a page to show another page as an inset and perform a seamless transition between an inset state and a navigated state.


Enable seamless transitions across navigations.



Specification link

Specification being incubated in a Community Group

Status in Chromium


In developer trial (Behind a flag) (tracking bug)

Consensus & Standardization

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

  • No signal
  • No signal
  • Mixed signals


Intent to Prototype url

Intent to Prototype thread

Search tags

portal, portals,

Last updated on 2021-12-13