> For the complete documentation index, see [llms.txt](https://guides.clickatell.com/flow/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guides.clickatell.com/flow/configuration/set-up-session-timeout-events.md). # Set up session timeout events {% hint style="info" %} Supported on **WhatsApp** and **SMS**. {% endhint %} The **Session Timeout Event** sends a courtesy notification to end-users when their session is about to expire. The default **channel session length** is 10 minutes. This means the session will automatically end if there's no activity (i.e., no inbound messages from the end-user) within this timeframe. Whenever the end-user sends a message, the session timer resets and the countdown starts again. You can configure the system to send a final “goodbye” message to the end-user at a specified time before the session expires, keeping them informed and engaged. ## Set up session timeout events {% hint style="info" %} Session Timeout Event configuration functions independently in the **Sandbox** and **Production** environments. This allows the flow-builder to activate the feature in Sandbox for testing proposes while it's deactivated in Production, or vice versa. {% endhint %} 1. Under *Configuration* on the left, select *Settings*. 2. Select *Timeout Event.* 3. Use the toggle to enable/disable the timeout event. * When enabled, the timeout event flow is triggered at the desired time (e.g., 70 seconds before session expiration). * When disabled, no message will be sent before session expiration. 4. Select the duration from the drop-down. * This is how long before the channel session expires you want to trigger the timeout event flow. 5. Click *Open Flow* to open and customize the pre-built placeholder timeout. * This flow triggers automatically when the timeout duration (as set above) is reached.