A toggle is a control that allows a user to update preferences, settings, and other kinds of information. When used well, toggles can make your interface easier to use and understand. Toggles are best suited for actions that require users to choose between two opposing states (like the Airplane Mode toggle in iOS) rather than selecting no or yes to a question (like a checkbox).

There are many ways to implement a toggle but it is important to make sure that the design of your toggle reflects its purpose and that the behavior is clearly aligned. Toggles should be clear and direct with clear color indications that signal state changes. They should also be sized appropriately for touch-screen devices.

Toggles can be a great tool to enable experimentation and the ability to iterate quickly. However, it’s critical to plan for how you will manage the toggling of a feature flag across different deployment environments. If you don’t have a way to dynamically re-configure your toggles in-memory at runtime, it can be hard to manage them and may impact the speed of your testing and feedback loop.

When you’re planning a new release it’s wise to test your feature toggle configuration in the expected production environment. This includes the current toggle configuration flipped On as well as any future toggles you’re planning to have flipped On. It’s also helpful to perform some tests with all toggles flipped Off in order to avoid any unexpected regressions in the future.