Atomics support [#3555961]

Seeing as Atomics is now widely available I think we should add some response headers so partytown can make use of it.

For me the biggest benefit would be getting rid of the very annoying proxytown requests but it may also bring some performance gains.

Any thoughts @abenbow?

Issue fork partytown-3555961

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Comment #1

4 November 2025 at 11:52

rattusrattus created an issue. See original summary.

Comment #2

abenbow

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commented 10 November 2025 at 14:49

Hey @rattusrattus, this looks really interesting! I wasn't aware that this was a feature we could support.

I'm taking a look at the docs on partytown and this looks pretty promising as something we could roll into the existing module.

It looks like if anything with the atomics system goes wrong, partytown falls back to the traditional service worker system, which is good in terms of feature detection and legacy support.

If I'm reading this correctly, we're essentially enabling two headers sitewide, correct? If so, I think we may need to provide a way for users to toggle that particular feature so they have some more fine grained control over if/when those headers show up in the response. At minimum, I'd propose a module hook so that administrators have some control over the experience for a given page or pages. A toggle in the admin UI would also be good.

What are your thoughts?