A custom element site widget 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 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 in Build Apps. Blocks apps build site widgets in the Blocks editor, which is a different implementation.
extensions.customElement() configuration fields.Last updated: 2 November 2026