A toggle is a switch that can be flipped to one or the other of two states or options. They are commonly used in technology, computing and programming to enable/disable features or modes. In web design we often use toggles to provide additional navigation, display options or content on a page. In user interfaces it is important to consider how and when toggles are appropriate. They should be used sparingly and when they are it is essential to have clear, direct labels and consistent visual design.
The word toggle comes from the Latin verb toggle, meaning “to bind or fasten.” In computer programming terms, a toggle is usually a Boolean variable that can be either True or False. Toggles are useful because they can be easily updated without affecting other code in a program, and are easy to test. Toggles are also convenient for testing and experimentation because they can be deployed to a small set of users and then turned on or off at will.
A common way to use a toggle is to implement it as a feature flag in an experiment. This allows us to track the behavior of cohorts of users and determine which codepath is more effective. However, we must be careful not to create a large inventory of toggles and ensure that there is a process in place for pruning them as soon as they have served their purpose. Otherwise, we risk introducing a great deal of complexity to our system.