Toggle is a term used to describe a software- or hardware-based control that allows the user to switch back and forth between two opposing settings. Toggles are commonly used in settings menus, options screens, and various other types of settings and preferences. When using toggles, it’s important to be clear about what each state means, provide direct labels, use standard visual design, and deliver immediate results.

Often times, designers add color to toggles to help users understand their state, but this can be confusing. In particular, many people have red/green color vision deficiency, so it can be difficult for them to determine what the toggle’s current state is. It’s also important to consider societal and cultural differences when choosing colors to represent states.

One of the most common uses of Toggles is for multivariate or A/B testing. By exposing different codepaths to different cohorts of users we can compare the effect of each. This is a powerful way to make data-driven decisions about things like the purchase flow of an ecommerce site or Call To Action wording.

Savvy teams view the set of Feature Toggles in their codebase as inventory that comes with a carrying cost, and strive to keep it as low as possible. Whenever a team decides that a toggle is no longer needed, they should be proactive in adding it to their backlog for removal. Some teams even go as far as to put “expiration dates” on their toggles, ensuring that they’re removed before they can cause any confusion or unexpected behavior.