# MKPlayer customization

The `@mediakind/mkplayer-customui-plugin` lets you build and customize playback interfaces on top of Bitmovin Player UI V3.

Previously, MKPlayer supported a basic `ui: true | false` flag to show or hide the default playback UI. The MKCustomUI plugin extends this by enabling full layout, control, behavior, and styling customization.

## What you can do

- Build MKPlayer's default-style UI
- Create fully custom playback UIs
- Configure UI behavior through `uiConfig`
- Use responsive UI variants for mobile and browser layouts
- Style playback controls using CSS class overrides
- Apply UI updates dynamically at runtime based on screen size, app state, and user context

## In this section

- [Install and initialize](/mkio/reference/player-customization/installation-and-initialization): Install the plugin, disable the default UI, and initialize MKPlayer and MKCustomUI.
- [UI configuration and variants](/mkio/reference/player-customization/ui-configuration-and-variants): Configure `uiConfig`, build responsive layouts, and use lifecycle events.

* [MKCustomUI API](/mkio/reference/player-customization/mkcustomui-api): Reference list of constructors and UI factory methods.
* [CSS customization](/mkio/reference/player-customization/css-customization): Apply CSS overrides for seekbars, typography, and branded visual styling.

## External references

- NPM package: [@mediakind/mkplayer-customui-plugin](https://www.npmjs.com/package/@mediakind/mkplayer-customui-plugin)
- API docs: [MKCustomUI API reference](https://mkplayer.azureedge.net/$web/websdk/plugins/customui/latest/docs/index.html)
- Sample code: [MKPlayerSamples custom UI example](https://github.com/mediakind-video/MKPlayerSamples/blob/main/Web/index_customUI.html)