Identify the App Instance in a Site Widget Built with the CLI

For security reasons, the app instance ID isn’t directly accessible in site widgets or settings panels. Instead, you can securely extract it by sending a Wix access token to a backend API. The backend can decode the token, retrieve the instance ID, and perform any necessary business logic.

This article explains how to:

• Backend: Expose a backend API that securely extracts the app instance ID from a Wix access token.
• Frontend: Pass the Wix access token from your custom element to your backend.

Step 1 | Expose a backend API to extract the app instance ID

To securely identify the app instance:

1. Add a Backend API Extension in the Wix CLI.

2. In the api.ts file of your backend API extension, import the auth submodule from the Essentials SDK:

   Copy

3. In the GET endpoint, call getTokenInfo(), which extracts instanceId from the access token:

   Copy

4. Use the instanceId and return the relevant data.

Step 2 | Pass a Wix access token from your custom element to your backend

To send the app instance ID to your backend, include a Wix access token in the request.

1. Add a Site Widget Extension in the CLI. If you already have a site widget, skip to the next step.

2. In the element.tsx file of your site widget extension, import the httpClient submodule from the Essentials SDK:

   Copy

3. Call fetchWithAuth() to send a request to your backend with a Wix access token:

   Copy

Example

The following sections contain example backend and frontend code for retrieving the app instance ID from a custom element.

Backend code

The following example is based on a CLI backend API extension called get-instance.

Frontend code

The following example creates a custom element to display the mock instance data from the get-instance endpoint.

See also

• About Site Widget Extensions
• About App Instances