Scoped custom element registries

[github-actions]

This GitHub issue is for collecting web developer signals for Scoped custom element registries.

The CustomElementRegistry() constructor creates a new custom element registry that's separate from the global window.customElements registry. Creating more than one registry is useful for multiple custom elements that have the same tag name to coexist.

Browser support

• Chrome: not supported
• Chrome Android: not supported
• Edge: not supported
• Firefox: not supported
• Firefox for Android: not supported
• Safari 26 (Sep 15, 2025)
• Safari on iOS 26 (Sep 15, 2025)

Give us feedback

If you're pressed for time, but you want this feature to be available in all browsers, please give this issue a thumbs up 👍 reaction.

However, a much better guide for us is to know how you'd use this feature, and what you're having to do in the meantime. This helps us judge the priority versus other features.

Copy the template below in a comment, and add the details that matter to you.

## What I want to do with this feature

<!-- Add your specific use-cases, even if they seem obvious to you. -->

## What I'm having to do in the meantime

<!--
Are you having to use another feature instead, a polyfill, or is it blocking you completely?
Why are the alternatives worse than using this feature?
-->

Learn more

You can learn more about this feature here:

• web features explorer
• webstatus.dev
• Specification