What Is a Toggle?

Toggle is a user interface element that allows a user to quickly update settings and preferences. It’s a simple and clear solution to a relatively common user-interface challenge, especially for settings that only have two opposing states (on or off). While toggles are a great choice for binary options that are easy to understand, if you need to support multiple states consider alternatives such as a checkbox or radio button instead.

In the 18th century, a toggle was a pin passed through the eye of a rope to hold it in place, or to secure it round a stay, mast, or bight. The word is now also used for a type of fastener, and for a switch that can be moved between two positions. On a computer, it refers to an on-off command, such as the key that turns your caps lock on or off.

In software, toggles are commonly seen in options menus in apps and online services. However, they can be useful in any interface where the user is able to select between two or more opposing states. When using toggles, designers should take care to provide users with clear and consistent visual signifiers and ensure that they deliver an immediate effect.

When choosing colors to represent the toggle state, it is important to keep in mind that not all people see things the same way, so be careful to choose colors that have high contrast and are recognizable across a range of devices and screen sizes. It’s also a good idea to avoid using purely literal symbols for the state, such as on and off, since those can lead to confusion and error. Likewise, it is important to consider the societal and cultural implications of a given color, such as red, which can be interpreted as an on or off signal in some cultures.

Many teams use static files to manage their toggle configuration, but this approach is cumbersome once you reach a certain scale. Modifying those files can be time-consuming and ensuring consistency across a fleet of servers is challenging. Savvy teams therefore opt to move their toggle configuration into some kind of centralized store, often an existing application database. This makes it easier to modify and debug, and can also help to reduce the number of toggles that are being used in production.

Toggle configuration is usually short-lived compared to other categories of Feature Flags, so teams should be proactive in removing them once they’ve been rolled out and tested. Some teams add a toggle removal task to their backlogs whenever they roll out a new release, while others use “expiration dates” to warn testers that a particular toggle is about to expire. Whatever the approach, it’s vital that your team has a mechanism to manage and control toggles in order to achieve the best possible outcomes from your Feature Flag investments.