Visual regression testing is a type of testing that focuses on detecting unintended visual changes in an application's user interface (UI) between different versions or configurations. It involves capturing screenshots or snapshots of the UI elements in the application and comparing them against baseline images or "golden" images.

During testing, the current UI snapshots are compared pixel-by-pixel with the baseline images to identify any discrepancies or differences. These differences may indicate visual regressions, such as layout shifts, font changes, color variations, or unexpected UI element modifications.

Visual regression testing helps ensure consistency and maintain the visual integrity of an application's UI across various platforms, screen sizes, and environments. It is especially useful in projects with frequent UI updates, multiple contributors, or complex UI components where manual verification of visual changes may be time-consuming or error-prone. By automating the detection of visual regressions, teams can identify and address UI issues early in the development process, ensuring a more polished and visually appealing user experience.