# Theme-Cosmos and UI KIT Co exist

**URL:** <https://forums.pega.com/t/theme-cosmos-and-ui-kit-co-exist/8304>\
**Category:** User Experience\
**Tags:** financial-services, 8-8-1, user-experience, pega-platform\
**Created:** [September 19, 2024, 11:56am UTC](https://forums.pega.com/t/theme-cosmos-and-ui-kit-co-exist/8304 "2024-09-19T11:56:33Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![BrahmeshTech](https://avatars.discourse-cdn.com/v4/letter/b/13edae/32.png) [@BrahmeshTech](https://forums.pega.com/u/BrahmeshTech)\
**Post date:** [September 19, 2024, 11:56am UTC](https://forums.pega.com/t/theme-cosmos-and-ui-kit-co-exist/8304/1 "2024-09-19T11:56:33Z")

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Is it possible to have both Theme-Cosmos & UI-KIT in the same application stack ? Application is built on UI-KIT and now we would like to use Theme-Cosmos for new UI changes in the application instead of migrating whole application UI to Theme-Cosmos as we would like to migrate the smaller chunks of UI components.

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**Author:** ![Sai\_Guggilla](https://yyz2.discourse-cdn.com/pega/user_avatar/forums.pega.com/sai_guggilla/32/11575_2.png) [@Sai\_Guggilla](https://forums.pega.com/u/Sai_Guggilla)\
**Post date:** [September 23, 2024, 9:36am UTC](https://forums.pega.com/t/theme-cosmos-and-ui-kit-co-exist/8304/2 "2024-09-23T09:36:51Z")

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@Brahmesh@

Yes, it’s possible to have both Theme-Cosmos and UI-Kit coexist in a Pega application for gradual migration, but it requires careful planning to avoid compatibility issues and to maintain a consistent user experience.

Create a Hybrid Application, Ensure that the application inherits both the UI-Kit ruleset and the Theme-Cosmos ruleset. Continue using UI-Kit for legacy sections while using Theme-Cosmos for newly developed UI components. Begin by converting smaller, less complex sections or features to Theme-Cosmos. Prioritize case types or screens that will benefit most from the new Cosmos UX experience.

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**Author:** ![RichardMarsot](https://yyz2.discourse-cdn.com/pega/user_avatar/forums.pega.com/richardmarsot/32/23530_2.png) [@RichardMarsot](https://forums.pega.com/u/RichardMarsot)\
**Post date:** [September 26, 2024, 12:47pm UTC](https://forums.pega.com/t/theme-cosmos-and-ui-kit-co-exist/8304/3 "2024-09-26T12:47:31Z")

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@Sai Guggilla create a built-on app where you will use the new Cosmos skin and UserPortal - Make sure that Theme-Cosmos is on higher than ui-kit in the ruleset stack

for more details

[Pegasystems Documentation](https://docs-previous.pega.com/user-experience/87/updating-theme-cosmos-your-application)?

> **[Migrating a simplistic app from UI-Kit to Theme-Cosmos in Pega Infinity...](https://support.pega.com/discussion/migrating-simplistic-app-ui-kit-theme-cosmos-pega-infinity-traditional-ui-architecture)**
>
> Pega Infinity's Section rule UI architecture -- based on Section rules, Skin rules, Dynamic Layouts, etc -- includes two "themes" for employee-facing enterprise applications:  UI-Kit and Theme-Cosmos.  The attached article provides guidance for...

> **[Ask the Expert - Cosmos UI with Sam | Support Center](https://support.pega.com/discussion/ask-expert-cosmos-ui-sam)**
>
> Join Sam in our first Ask the Expert session of 2020 (3rd - 14th Feb) on Cosmos UI Meet Sam: Sam is a Senior Product Manager for Cosmos UI and UI-Kit at Pega. His extensive career background includes web and mobile software engineering and...

> **[Ask the Expert - Pega Cosmos with Sakthi Vickraman | Support Center](https://support.pega.com/discussion/ask-expert-pega-cosmos-sakthi-vickraman)**
>
> Join @SakthiVickraman as he answers your questions regarding Pega Cosmos!   Make sure to Favorite  and  Follow  for updates via the Notification bell and/or weekly digest! Session dates: 17 July - 28 July