Toggle is a term used to describe switches that only have two positions, either on or off. You may use a toggle in a physical sense, like a pin passed transversely through an eye or loop in a rope, or in a software context, as seen in most settings menus where users are able to switch between different functions.
A toggle can also be used as a verb, which means to alternate between one state and another, such as when you toggle between screens as you video chat with two friends at once. However, in computer technology the word is most commonly used to refer to a piece of code that sends a user down one path or another. This is a technique often used in multivariate or A/B testing and can help make data-driven optimizations to things like purchase flow or call to action wording.
When using toggles it’s important to keep in mind that they should always have a direct label and be clearly differentiated from other controls by their position on the screen, color, and movement. Designers should also consider a number of other factors when creating toggles, including contrast, cultural implications, and how they relate to other design patterns, such as sliders or checkboxes.
Toggle configuration can be managed in a variety of ways, from simple commenting through to more complex approaches such as using a preprocessor’s #ifdef feature. Generally speaking, any toggle configuration that will be live in production should be tested with both its current On and Off states, although it’s also a good idea to test the fallback configuration with all toggles flipped Off.
In order to avoid breaking existing code, many teams choose to move toggle configuration into some sort of centralized store, which is often an existing application DB. This allows for a more dynamic approach to toggle configuration and can make it easier for product managers, testers and system operators to manage and modify the behavior of these features.
Managing toggle configuration via files can quickly become cumbersome when a team reaches a certain scale and requires an approach more dynamic than simply changing a flag in source control. To address this issue, many teams opt to create some form of admin UI which allows product managers and test engineers to view and change toggle configuration, as well as to deploy the configuration to their production environment in an automated manner.