Toggle is a term used in computer technology to describe an on-off command. For example, if you toggle on caps lock, you are switching that function on and off. In software, toggles are commonly used to update user preferences or settings. Toggles should be clearly labeled, utilize standard visual design, and deliver immediate results to users.

In addition to being a simple UI control, toggles are also often used in more complex ways such as in A/B testing and other forms of data-driven optimization. In these cases, toggles are used to route a given user down one of two codepaths at runtime based upon the results of an experiment.

Regardless of where they are deployed, the goal is to make it as easy as possible for users to update their preferences and settings. This is often accomplished by making toggles appear like sliders with clear movement and color cues. Toggles can also be incorporated into navigational elements such as tables of contents and accordions to minimize scrolling and maximize usability.

Savvy teams view their feature flag inventory as a carrying cost and seek to keep that quantity as low as possible. As such it is common for them to add a task on the backlog whenever a Release Toggle is added, and to remove them from the backlog as soon as they are no longer required. In some cases, they even put “expiration dates” on their toggles and create test failures if the feature is still enabled past that point.