# Customize Sisense with JavaScript
Sisense has a rich set of JavaScript client APIs which can be used to customize the behavior and look of Sisense UI elements using dashboard and widget extensions, add-ons, and when embedding with Sisense.js.
Some common customizations include:
- Adding custom widget types that can be used in dashboards
- Adding or hiding UI elements such as menu options
- Modifying widget metadata and configuration at runtime via various events
This section includes an API reference for the APIs themselves as well as guides and references for other aspects of the extensions and add-ons framework, such as the common file structure for Sisense add-ons.