A toggle is a switch that has two positions, either on or off. It’s used in user interfaces, for example to turn a notification on or off. It’s also a verb, as in “to toggle between screens while video chatting with two friends at once.”
Web designers often use toggle buttons to hide or show article content—think of it like a collapsible panel or accordion. When they work well, they minimize scrolling and help readers focus on the content that’s relevant to them. However, if these buttons aren’t designed properly, they can be confusing and even frustrating.
The word toggle comes from the 18th century term for a pin passed through the eye or loop of a rope to hold it in place, but now we usually think of it as a kind of on/off fastener. It’s also a common part of keyboard shortcuts to change the settings for a program or app. In computer programming, a toggle function flips a variable’s state between two states—like true and false or on and off.
For most web and mobile developers, the first thought when they hear the word toggle is that of a button that’s on/off. But there are many kinds of toggles: a switch for turning an on/off light on or off, a button that switches a feature on or off, a switch that turns a screen on or off, etc. It’s important for designers to choose the right visual clues to communicate the toggle’s current state—it’s not as easy as picking a color.
In addition to their visual cues, toggles should be clearly labeled with an icon or text that indicates the current state. This helps reduce cognitive overload, which can occur when users see more than one toggle with similar looks and behaviors and have to guess which of them is currently active. It’s also critical to make sure a toggle is only in the active state if it has to be and that it has the required functionality to do so.
Some teams use toggles to perform continuous deployment, allowing them to introduce new features slowly to large numbers of users. For example, Facebook rolled out its redesign of the news feed by introducing it to some users with a toggle before making it available to everyone. Etsy also uses a toggle-based release process to test out and optimize its site features before rolling them out to its entire user base.
A good rule of thumb for managing feature toggles is to limit the number of states a toggle supports to just four or less. This will prevent teams from creating too many different states and make it easier to debug them down the line. It’s also a best practice to give each toggle a name that tells someone on the team what it does and who wrote it. This can help when the feature is accidentally activated in production and creates unexpected behavior.
