Toggle is a term in technology, computing, and programming that refers to a button or switch that toggles between different states or options. A toggle can be activated to turn something on or off, and is generally used to control a state of a view, a piece of content, or a whole application.

Toggles are also commonly used to perform A/B testing on a product. By toggling a feature on or off on a large group of users the engineering team can test new code without exposing everyone to it. Once the experiment has finished the engineering team can then deploy the new code to all users.

As your program grows it becomes more difficult to manage toggle configuration via static files, so many teams move toggle configuration into some sort of centralized DB or existing application config system. This helps reduce friction for future releases as the team will be able to easily verify how a release will perform with all toggles flipped Off and all toggles flipped On.

When using toggles make sure to clearly identify the view or piece of content that a toggle affects. You should also supply a label text alongside the toggle to further clarify what it does (i.e. toggle on, toggle off). For more complex toggles that do not operate on a singular view, consider using a more appropriate component like a popup button. Additionally, it is best to avoid making toggles confusing by relying on color alone. For example, a toggle that uses red and green to indicate on and off is inaccessible for people who have color vision deficiency.