Toggle is an interface element that allows people to manage the state of a view, content or setting. Toggles can be used to hide or reveal additional information, to toggle between different views of a page, and to change the behavior of an object (such as a slideshow).

It’s generally best practice to use a toggle only when you are implementing features that you want to be able to turn on and off. This prevents you from creating large swaths of code controlled by a complex set of toggles. It also helps prevent people from changing the behavior of your product by accident.

Using a toggle to implement features in this way also supports newer agile development models where teams work on individual, user-driven features in parallel to other core functionality. This would be difficult or impossible to do with more traditional waterfall development processes.

When designing a toggle you should always clearly identify the setting, view or content that the toggle is affecting and update its appearance based on its current state. It’s also important to make sure that the toggle is accessible to users with impaired vision or cognitive issues — it can be very confusing for them if the toggle icon doesn’t communicate its purpose and they aren’t able to tell if it is on or off.

Managing toggle configuration via static files becomes cumbersome at a certain scale, and it’s often preferable to move the toggle into some kind of centralized store — either an existing application DB or a dedicated toggle management UI.