# Use case examples

### Send notifications from the overlay SDK to a composition script <a href="#send-notifications-from-the-overlay-sdk-to-the-composition-script" id="send-notifications-from-the-overlay-sdk-to-the-composition-script"></a>

This example uses video.js callbacks to listen to specific player events. The Overlay SDK sends a notification to the composition script when an event occurs. The composition script then updates control nodes in the composition to trigger the indicators.

[Contact the Singular support team](https://developer.singular.live/support/support-resources#developer-support) for a copy of the composition.

Use the player controls and watch the status indicators changing.

{% embed url="<https://codepen.io/Singular/pen/dyoXjZW?editors=1010>" %}

### Send messages from composition scripts to the overlay SDK <a href="#send-messages-from-composition-script-to-the-overlay-sdk" id="send-messages-from-composition-script-to-the-overlay-sdk"></a>

This example shows how to receive messages from a composition script to the overlay SDK.

[Contact the Singular support team](https://developer.singular.live/support/support-resources#developer-support) for a copy of the composition.

Click on the interactive icons build within Singular to play the according clip in the video.js player.

{% embed url="<https://codepen.io/Singular/pen/NWqrBgO?editors=1010>" %}