Client Rects is a browser API that provides layout information of web elements, including their position and size. This information is referred to as "rects".

Due to differences in hardware configuration, OS, browser types and versions, screen resolution, font settings, Flash, interface language, and other factors, the layout information of web elements may differ when the same webpage is opened on two different devices. This difference generates a unique identifier known as the ClientRects fingerprint, which can be used for browser fingerprint tracking.

In the SupLogin client, you can configure ClientRects settings. By selecting "Random," matching values will be used to replace your real ClientRects. Selecting "Close" will use the default ClientRects of the current computer for each browser.