The word toggle is used to describe an object that moves between two states (such as a switch on a light that switches between ON and OFF). The control is most commonly found in digital products that allow users to modify settings or preferences, such as a mobile app’s Airplane Mode settings.
However, it’s important to keep in mind that toggles are not the right choice for every situation. For example, using a toggle to download content is a misuse of the control because downloading is a one-time action and doesn’t have a persistent state. Toggles are best for changing state-dependent functions such as setting or disabling features that are automatically enabled or disabled based on system conditions.
Toggles are a great tool for communicating complex behaviors to users and can help reduce cognitive overload by simplifying the user experience. But they’re not a magic bullet and should be avoided when possible to avoid confusing and frustrating users.
The use of color to indicate a toggle’s state is a common design pattern, but we recommend you consider other visual cues as well. For example, our research showed that the color white is unreliable at conveying the active state and may skew user intuition — especially when the toggle is not inverted. Instead, it’s recommended that you use a bold-thin color combination to distinguish the active toggle from the inactive one. And as always, when introducing new UI elements it’s important to test them with real users before you launch them in production.
If you do choose to use a color-based toggle, you should use it sparingly and always with a clear label that clearly describes what the toggle’s current state is. Also, be aware that embossment has been found to be unreliable at signaling the active state, so it should be paired with another primary visual cue such as a solid border or color fill.
Toggle Configuration
The ability to dynamically re-configure specific service instances is a powerful feature that can be a source of confusion in shared environments when it’s not used correctly. To prevent this we encourage teams to build out some form of centralized configuration management which allows system operators and testers to view and manage Feature Flags and their toggle configuration. This could be as simple as adding comments to the code, or in more sophisticated cases a centralized DB that is accessed by an admin interface.
A savvy team will recognize that each Feature Flag comes with a carrying cost and will seek to minimize the number of toggles in production by regularly reviewing their usage. This might mean adding a toggle removal task to the backlog when a toggle is first introduced or creating “expiration dates” on toggles that are no longer in use. This ensures that all users are exposed to a consistent set of behaviors.
