Toggle is a word used to describe a switch that can be in two positions, either on or off. A toggle can be found in hardware such as a keyboard’s caps lock or num lock key, or software like a video chat that allows you to switch between your two screens as you talk to someone on the other end of the world. Toggle is also the name of an experimental feature management tool that is commonly used to enable A/B testing at scale in a continuous delivery system.

Toggles are a valuable tool to help teams make data-driven optimizations and to quickly roll out those changes into a live production environment. However, a team should always ensure they are using them appropriately and with care.

If a toggle switch is being used to control something that doesn’t change state at all (like downloading content) then it is most likely not the best tool for the job. A toggle should only be used for changes that will have a lasting impact on the user’s experience.

When designing a toggle, designers should be careful about the visual cues they use to communicate its current state. A good place to start is by using high-contrast colors to denote states, and be sure to consider societal and cultural implications of the chosen color. It is also important to limit the number of words used in a label, and that the words are direct and easy to understand.