> Portal Navigation:
> 
> - Append `.md` to any URL under `https://dev.wix.com/docs/` to get its markdown version.
> - Pages are either content pages (article or reference text) or menu pages (a list of links to child pages).
> - To get a menu page, truncate any URL to a parent path and append `.md` (e.g. `https://dev.wix.com/docs/sdk.md`, `https://dev.wix.com/docs/sdk/core-modules.md`).
> - Top-level index of all portals: https://dev.wix.com/docs/llms.txt
> - Full concatenated docs: https://dev.wix.com/docs/llms-full.txt

## Resource: About Custom Element Site Widgets

## Article: About Custom Element Site Widgets

## Article Link: https://dev.wix.com/docs/site-extensions/custom-elements/about-custom-element-site-widgets.md

## Article Content:

# About Custom Element Site Widgets

A [custom element site widget](https://dev.wix.com/docs/overview/extensions-framework/site-extensions/site-widgets.md) is a UI component that Wix users place and resize on a site page. The widget is a custom HTML element, and Wix users configure it through a settings panel you provide. This reference is the contract for that extension in a Wix CLI app. It covers the generated files and the configuration object.

An [Editor React Component](https://dev.wix.com/docs/site-extensions/editor-react-components/about-editor-react-components.md) is a separate extension. Wix users also place it on a page, and the editor builds the panels from a manifest. Editor React Components are the placeable widget on Studio Two, and they also run on Wix Harmony. A custom element site widget runs on Wix Studio, Wix Editor, and Wix Harmony sites.

A Studio Two site doesn't use this extension. Add an Editor React Component there instead. Wix-managed and self-managed headless projects don't support site extensions. Self-managed apps host the element script and the settings panel on their own server, and configure the widget in the App Dashboard instead of these files. See [Add Self-Managed Site Widget Extensions with Custom Elements](https://dev.wix.com/docs/build-apps/develop-your-app/develop-a-self-managed-app/supported-extensions/site-extensions/site-widgets-and-plugins/add-self-managed-site-widget-extensions-with-custom-elements.md) in Build Apps. Blocks apps build site widgets in the Blocks editor, which is a different implementation.

## What's in this reference

- [Custom Element Site Widget Extension Files and Code](https://dev.wix.com/docs/site-extensions/custom-elements/custom-element-site-widget-extension-files-and-code.md): The generated file set and the `extensions.customElement()` configuration fields.

## See also

- [Site Widgets](https://dev.wix.com/docs/overview/extensions-framework/site-extensions/site-widgets.md)
- [Editor React Components](https://dev.wix.com/docs/overview/extensions-framework/site-extensions/editor-react-components.md)
- [Custom Element Site Widget Extension Files and Code](https://dev.wix.com/docs/site-extensions/custom-elements/custom-element-site-widget-extension-files-and-code.md)
- [Add a Custom Element Extension with the Wix CLI](https://dev.wix.com/docs/build-apps/develop-your-app/develop-an-app-with-the-cli/supported-extensions/site/custom-elements/add-a-custom-element-extension-with-the-wix-cli.md)