# Reading Session Identifer

If you are planning to add events from your backend application and if you want to associate that event with the Growlytics Session, this article will guide you on how you can achieve that.

## Passing Session Identifier to your server

The Session identifier is nothing but the device id of the customer that Growlytics maintains. You can use `Growlytics.getDeviceId()` to read the device id.

```javascript
let deviceId = Growlytics.getDeviceId();
```

{% hint style="warning" %}
Device Id is always associated with a single customer and its a permanent for the given browser/device. If in the same browser, if the user logs out and logs in as another user, then the device id will remain the same but it will be pointing to a newer user.
{% endhint %}

You can pass the device id received to your backend server and use it while adding an event to Growlytics from your backend.