In software, a toggle is an on-off command that turns something on or off. For example, the caps lock and num lock keys on your keyboard are toggles for specific functions. A toggle can also refer to an interface element that gives a user control over multiple aspects of an experience, such as the option menus found in many software programs.
The word “toggle” has an 18th century root in the English language, referring to a pin passed transversely through the eye of a rope to fasten it. It was used in this way to secure a load or a chain, as well as to fasten or unfasten parts of a machinery or mechanism. Today, the word is used more generally to describe a switch that alternates between two states. A common example is a light switch, where you can flip between on and off. The term is also often used to describe an up-and-down command, such as a scrolling bar that allows you to adjust a setting or page view.
Toggle is a very powerful and flexible control. It is a good choice for situations where the goal is to make an immediate change without needing to hit Save, Submit or other buttons. However, the complexity of the interaction can increase if users have to spend time thinking about which toggle they want to select. To avoid confusion, toggles should be used with primary visual cues that communicate the current state clearly and consistently.
Typically, toggles are used to present options with mutually exclusive outcomes — such as “yes” or “no” — and use a different appearance to indicate each of those states. They are most effective when they are placed at the top or bottom of an interface and when their appearance is consistent across platforms. It is also important to avoid relying solely on color to convey the current state of the toggle, as this can cause users to misinterpret its current behavior or assume that it is inactive when it actually is active.
There are a few different ways to manage the configuration of a toggle (the state that it is in when it is pressed). A very simple approach is to hardcode the toggle’s configuration in the source code, using something like a preprocessor’s #ifdef feature. While this approach can be effective for some types of toggles it doesn’t allow for dynamic re-configuration, which is usually necessary for more long-lived or product-centric toggles like Permissioning Toggles.
Another method for managing the configuration of a toggle is to use a feature flag. This allows us to change the toggle’s state for a specific cohort of users at runtime and measure the effect on that group’s behavioral metrics. This is similar to a Canary Release but with the advantage that it can be applied at scale for more than just a few weeks.
