The src/extensions/ folder is the default location for extensions you generate with wix app generate, organized by where the extension runs: backend/, dashboard/, and site/. Each extension gets its own folder holding an <extension-name>.extension.ts configuration file and its implementation. For example, an event handler is created at src/extensions/backend/events/my-event/, with my-event.extension.ts and my-event.ts.
You can place extensions anywhere under src/, as long as you update the paths in their .extension.ts files and their import paths in extensions.ts.
An extension's .extension.ts file declares it with a builder from @wix/custom-extensions. extensions.ts imports the file and registers the extension. For example:
An extension's id identifies it as a component of your app across releases, so it stays fixed once the extension is released.
wix app generate creates each extension's files, including a .extension.ts file containing the builder. By default, it uses the naming pattern [extension-name].extension.ts, and you can rename these files.
Last updated: 10 November 2026