It is possible to customize Jenkins' appearance with custom themes. This feature is not a part of the Jenkins core, but it is supported through plugins.
There are several plugins that provide built-in themes, the most popular are
Installing any of these will also install their common dependency: the Theme Manager Plugin. This plugin allows administrators to set the default theme for a Jenkins installation via Manage Jenkins > Configure System > Built-in Themes and users can set their preferred theme in their personal settings. You can also configure this plugin using Configuration-as-Code Plugin. See the plugin documentation for more details.
|Jenkins themes are provided “as is”, without warranty of any kind, implicit or explicit. The Jenkins core, plugins and other component updates may break theme compatibility without notice.|
At the moment, the Jenkins project does not provide specification for layouts/CSS, and we cannot guarantee backward or forward compatibility. We try to reflect major changes in changelogs (e.g. see the ‘developer’ changes in the Jenkins changelog), but minor changes may not be included there.
There is an ongoing effort focused on improving Jenkins look-and-feel, accessibility, and user experience. This area is mission-critical to the project. There are multiple initiatives in the Jenkins Roadmap being coordinated by the Jenkins User Experience SIG.
Major UI changes imply incompatible changes in layouts and the CSS structure which is critical for theme plugins. Historically Jenkins had no explicit support policy for themes, and we do not want to provide compatibility requirements which would create obstacles for reworking the main Jenkins interface. Later, once the Jenkins UI rework reaches its destination and the UI becomes more stable, we could consider creating specifications for theme extensibility so that we could make themes more stable and maintain compatibility.
For built-in themes, users are welcome to report discovered compatibility issues to theme maintainers, and to submit patches there.
We will generally reject bug reports to the Jenkins core/plugins involving broken UI elements with a custom theme. We will consider pull requests which restore compatibility and do not block further Web UI evolvement.
We encourage Jenkins users to create themes and to share them. Such themes could be a great way to experiment with UI enhancements, and we would be happy to consider enhancements from them for a default Jenkins theme.
To improve the user experience, please consider the following recommendations:
Explicitly document compatibility for themes.
Version themes with tags on Git and to maintain changelogs with explicit references to changes in the supported versions (e.g. see our release drafter documentation as one of the ways to automate changelogs).
Explicitly define an OSI-approved open source license so that users can freely modify and redistribute them.
This is also a prerequisite for hosting themes in Jenkins GitHub organizations and, in the future, theme marketplaces or other similar promotion engines.
If you would like to share a story about Jenkins themes, please let the Advocacy&Outreach SIG know!