Toggle is a type of user interface element that allows users to update preferences, settings, or other types of information. It typically enforces a mutually exclusive state, such as on or off. Toggles should be easily identifiable by their direct labels and consistent visual design, and they should communicate the current state clearly. For example, toggles should use high-contrast colors to signal state change and consider cultural implications such as red’s association with stop signs or traffic signals.
Savvy teams use toggles in a variety of ways in their continuous development practice, from experimentation to acting as circuit breakers in the codebase. They can also be used to validate features with a segment of their audience before rolling them out to the entire user base.
For example, our e-commerce company may decide that algorithm B is too resource-intensive to be included in their core product but would like to offer it as a premium feature. They can generate a new release toggle that enables the algorithm on the production server while leaving the default code behind. If they find that the feature isn’t performing as expected they can revert to the default without impacting their customers or delay the release of the rest of the product.
Toggles can be generated based on a wide variety of conditions, from simple “if” statements to complex decision trees that act upon many different variables. Oftentimes these decisions are based on fitness test results from other features in the codebase, or they can be generated from settings in a config file or feature flag service.
