A toggle is a physical button or piece of software found on devices and computers that allows users to switch between settings and features. It is often used to control functions that are on by default but can be turned off if desired. Examples of this include the Caps Lock and Num Lock keys on a keyboard or the Airplane Mode setting on a smartphone. Toggle is a popular control for adjusting system settings and preferences (ie states of system functionalities) as it takes less screen estate than a checkbox.

When using toggles ensure they are clearly labelled, use standard visual design and deliver immediate results. This is especially important for when a toggle switches between two opposing states such as ON and OFF. It is also helpful to make the difference between ON and OFF obvious by providing a different color or label for each state. This will avoid confusion and help reduce user error.

Since a toggle is a feature flag it comes with its own set of challenges. This includes having to test both paths of the configuration as well as ensuring that your feature flag management tool supports runtime re-configuration. This can take a toll on your validation and CI/CD processes. Savvy teams view toggles as inventory and try to keep their number low by adding a task on the backlog for removing toggles that are no longer in use or creating “expiration dates” for a toggle that will be automatically removed from a release after a period of time.