A toggle is a simple user-interface component that allows users to update their preferences, settings or other types of information. When used effectively, toggles can make a big impact on user experience. However, when misused they can lead to confusion and frustration. So it’s important to evaluate how you use toggles and keep them consistent across your site or app. Then you can build trust that your features will always deliver the same, predictable results.

Toggles can be triggered to switch to a different state by a wide variety of conditions. A fitness test result from another feature, a variable set by the feature management system, a default value in an config file – even an A/B experiment can trigger a toggle to flip between two states.

When a toggle is turned off it does not disappear from the application, but rather becomes slightly transparent. Toggling it back on will display the hidden content again. Toggles can also be triggered to appear on demand, allowing teams to deploy new features to a small group of users at any time. These features are called Champagne Brunches and are similar to a Canary Release in many ways.

While using toggles to roll out and roll back features is extremely valuable, it is important not to abuse them. For example, it’s often tempting to reuse a toggle that already exists to support a bug fix, but doing so can potentially introduce unwanted behavior or worsen the original bug. Instead, it’s best to decide on a case-by-case basis whether or not to create a feature toggle around a bugfix.