A toggle is a switch that has two positions, on and off. When a user clicks the toggle on or off they are enabling/disabling a feature in the application. It is important to understand the cognitive issues associated with using toggles in order to design a good interface.
The most common toggle is the checkbox. While it is a simple and intuitive mark, it does not work well in some cases. This is due to the fact that it does not provide any visual clues that indicate whether a toggle is active or inactive. In order to avoid confusing users it is crucial to design a toggle with appropriate visual cues.
Toggles are also a great way to manage feature flags in a development environment. The ability to turn a flag on or off for specific users allows developers to test new features without impacting production environments. Typically these toggles are short lived and are replaced with a full release when complete. In some cases the toggles may remain in place for longer periods of time, such as with product-centric features that need to be tested and stabilized for a period before they can be rolled out more broadly.
When used correctly the toggle can be a powerful tool to help improve interface design and user experience. However, when misused it can lead to confusion and mis-interpretation by users. For example, using a toggle to represent a download button can be misleading because it does not indicate that downloading will occur each time the toggle is clicked.
Using the toggle as an indicator of availability can also be problematic because users will be confused if the toggle is not immediately available for use. The best use of the toggle is to provide a clear indication that a feature is not yet fully developed and that it may be turned on or off at any time.
A final concern with the toggle is that it can be difficult to maintain a consistent state across a fleet of servers when managed via static files. This problem is typically resolved by moving the toggle configuration into some type of centralized store, often an existing application DB. This can be accompanied by the build out of some form of admin UI that allows system operators, testers and product managers to view and modify the toggle configuration in a consistent manner. This can greatly reduce the effort required to manage the toggles in a large scale environment.
