Ember: Framework overhaul to use vite

[mogstad]

What I did

Ember just released Ember 6.8 with Vite as its default build system as well as support for rendering components directly to DOM, as well as passing arguments as an object, which makes it perfect to use to render stories in Storybook. To my understanding the current Ember renderer isn't compatible with Storybook v10 and I've therefor completely replaced it.

The new integration uses Vite which makes it possible to integrate with Storybook v10. The new integration doesn't boot the app by default, the ergonomics of using an app should be explored further.

Supersedes #32790

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

1. yarn task --task sandbox --start-from auto --template ember/default-ts
2. Open Storybook in your browser
3. Ensure all stores are working as expected

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook publish.yml --field pr=<PR_NUMBER>

Summary by CodeRabbit

• New Features

  • Dynamic HTML source rendering for Ember docs; improved Glimmer source generation and a source decorator.
  • New client-facing APIs and TypeScript types for Ember stories (Meta/StoryFn/StoryObj) and portable stories support.
  • New example components and stories (Button, Header, Page) with interaction (play) tests.

• Chores

  • Migrated framework tooling and templates from Webpack to Vite; updated build and package exports and dependencies.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[gossi]

This is huge!!!

It's the foundation for integrating Ember with Storybook@10 through vite. Bringing all build systems together surely was a not-funny endeavor, so @mogstad did the herculean effort here.

This enables Ember for Storybook 10 in any form better than any previous implementation... and this is only the MVP. The more interessting work can start now.

Here is a list of things I see, we can do now (in no particular order):

• Typedoc integrations (args and slots in docs mode)
• Stories in gjs/gts (when you want to test/embed your components in HTML)
• Provide Decorators for Ember Devs (to support Embers DI system, or else components break 🙈)
  • Mock services
  • Set application (also globally, work for owner already done)
• Support CSF Next format for Ember
• Vitest integration

Basically, what Yann showed at Viteconf is now in reach for Ember: https://www.youtube.com/watch?v=YNQ_cJ6yy2Q

So, this PR unlocks the implementations I listed. We can do this in parallel now, thanks to the foundation of this PR.

PS. This started in september when I reached out to ask for help in integrating with Ember and took until today. Thanks a lot to @ndelangen and @JReinhold for providing their tremendeous support here, much appreciated.

But most credit goes to @mogstad 🥳 🎉 💯

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 2d599d2

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☁️ Nx Cloud last updated this comment at 2025-12-24 10:39:29 UTC

[storybook-app-bot]

Package Benchmarks

^{Commit: 8cd1b46, ran on 25 March 2026 at 09:03:26 UTC}

The following packages have significant changes to their size or dependencies:

@storybook/ember

	Before	After	Difference
Dependency count	189	15	🎉 -174 🎉
Self size	15 KB	39 KB	🚨 +23 KB 🚨
Dependency size	28.93 MB	27.42 MB	🎉 -1.51 MB 🎉
Bundle Size Analyzer	Link	Link

[ndelangen]

@mogstad @gossi Shall we schedule a meeting? Perhaps during one of the triage meetings in discord? to talk about this PR it's state and it's future?

I'm personally very excited about all this work being done, and looking forward to learning it's internals a bit and figuring out how to get this released.

[jonniebigodes]

@mogstad, can you take a look at #27186 and coordinate with @benedik to see if his work fits into this overhaul of the Ember framework?

[benedikt]

This PR is pretty much the "Long Term Solution" we described in #27186. We're happy to help with this one. Let us know how we can do so 😄

[valentinpalkovic]

Closing due to inactivity. Please feel free to open a new PR if you want to continue the work. Thanks for your contributions so far!

[gossi]

We were already in contact with @ndelangen via Discord. I pinged him this week.

I carefully hit reopen here, as talks happen currently in Discord (let's say we took an extended christmas break).

@valentinpalkovic I hope reopening this is ok for you :)

[LucasHillDex]

@mogstad @gossi any help needed to push this over the finish line?