StrataKit and MUI: A new beginning

[mayank99]

On December 1 2025, our CTO Julien Moutte announced the future of our design system:

First and most fundamental point: a fully standardized and uniformly adopted Design System is a must-have for us now. […]

After much consideration, we have chosen to use a third-party design system called Material UI (MUI) as the basis for our ‘Strata’ design system.

This is a drastic shift away from how we have been developing StrataKit. This post aims to bring clarity regarding the general direction going forward.

Design system vs component library

The biggest impact of this new direction will be felt at the component level. In practice, this means consuming teams (applications and packages) will use components directly from MUI.

So what is still the design system's responsibility? Previously, StrataKit could be thought of as a combination of design tokens, icons, and Ariakit-based components, with future plans for introducing guidelines, patterns and layouts. Going forward…

• StrataKit will no longer focus on building base/common UI components, and instead provide an MUI theme.
• The icon library will remain largely untouched (barring new additions).
• The design tokens will evolve to support the MUI theme.
• StrataKit will only provide bespoke custom components, where a suitable alternative doesn't exist in MUI.
• Guidelines and patterns remain an important goal for the design system, regardless of the component library implementation.
• Work on "layouts" has been deferred for the time being. We believe this is unaffected by the MUI decision however.

History

The original version of this post lacked clarity around the plan for custom components, guidelines and patterns. We have since learned that we will still need a few custom components to supplement the MUI-based component-library. The start of this effort is being tracked in #1355.

The original diagram has been included here for posterity.

The specifics

A new @stratakit/mui package has been published, which will be the primary entrypoint into the design system and expected to be used as a singleton/peer dependency. This new package will expose two components, Root and Icon, which have the exact same API as their @stratakit/foundations counterparts.

The Root component from @stratakit/mui will wrap the MUI ThemeProvider, pre-configured with a customized theme. This is what unlocks the consumption of @mui/material components further down the tree, while giving the design system the ability to evolve the visual theme over time.

As @stratakit/bricks and @stratakit/structures have seen significant usage (~5000 weekly NPM downloads), these packages will enter "maintenance mode" in the short term. This means the components will continue to work, but there will be no new features or bug fixes, except in very serious circumstances such as a security vulnerability, build errors, or a page crash. This approach allows for gradual adoption of MUI and gives us time to figure out alternatives.

In contrast, the @stratakit/react package will be deprecated entirely due to very low adoption (~50 weekly NPM downloads) and straightforward migration path back to @itwin/itwinui-react (which has the exact same API).

Lastly, the @stratakit/icons will remain intact. This package was purpose-built to be a standalone library of .svg icons (meticulously handcrafted by @msllrs) and will continue to be supported. We strongly recommend using this package over any other alternatives (whether that's @mui/icons-material or @itwin/itwinui-icons-react).

Package name	Replacement	Notes
@stratakit/foundations	🆕 @stratakit/mui	These packages have the exact same API.
@stratakit/icons	-	This package is entirely standalone and will remain intact.
@stratakit/bricks	@mui/material	MUI should have equivalents for most bricks.
@stratakit/structures	@mui/material	There will likely be components/features missing in MUI.
@stratakit/react ("API bridge")	@itwin/itwinui-react	These packages have the exact same API.

iTwinUI theme bridge

Throughout the tumultuous development of StrataKit, the iTwinUI theme bridge has always been the anchor point, providing a semblance of stability to teams that are already using it. This will continue to be the case during this new transition period.

We will make the theme bridge work with the new Root component from @stratakit/mui, allowing teams to mix and match components from @mui/material and @itwin/itwinui-react. The same design tokens will power both the MUI theme and the iTwinUI theme bridge, ensuring visual harmony between the two systems.

Final words

While there are a lot of unknowns that we are still working through, we feel confident in this general strategy. We will post updates here as we learn more.

The immediate next steps for the design system are:

• Publish initial version of @stratakit/mui
• Update @itwin/itwinui-react to support @stratakit/mui
• Provide basic documentation and support

Update (March 2026): StrataKit+MUI is now ready for early adoption.

Acknowledgements

I would like to personally thank everyone who has contributed to StrataKit (in particular @msllrs, @ahilhorst, @GerardasB, @FlyersPh9, @Heydon, @knowler, @r100-stack, and @mglancybentley).

I would also like to thank all our early adopters who believed in the StrataKit vision and gave us meaningful feedback.

I am very proud of what we've accomplished during the short life span of StrataKit, and I hope we will find a way to honor the original design vision and maintain a similar level of quality with this change in direction.