Extends WebAssembly to support PostMessage of WebAssembly.Module objects to Web Workers. To clarify, this is scoped to just Web Workers (same process, different thread), and not extended to cross-process scenarios (such as cross-origin postMessage, or shared web workers).


Specification link

Specification currently under development in a Working Group

Status in Chromium


Enabled by default (tracking bug)

Consensus & Standardization

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



This feature was originally included in the initial launch of WebAssembly, and was shipped in other browsers with their initial WebAssembly support.

Last updated on 2021-12-13