A toggle is a switch that has two positions: on and off. Toggle switches are often used in the user interface to update preferences, settings, and other types of information. When using toggles it is important to provide direct labels, use standard visual design, and deliver immediate results.

Toggles are a very effective way to update many types of settings in software applications, but they can be confusing for users if not designed properly. To avoid confusion it is best to stick with one side of the toggle being active and the other being passive, and to provide clear and direct labels that describe the current state.

Traditionally, the simplest way to manage a toggle configuration has been by hardcoding it into static files and modifying those static files as needed. This approach is fine in small applications, but it becomes cumbersome once the number of toggles grows to a certain size. For this reason, as apps and sites grow in scale it becomes increasingly common to move toggle configuration into some type of centralized store, often an existing application DB. This is usually accompanied by some form of admin UI which allows system operators, testers and product managers to view, change and manage toggle configuration.

In addition to centralized storage, it is also possible to manage a toggle configuration using a preprocessor feature such as #ifdef. This allows the UI to automatically determine whether a toggle is active or passive, and the application to re-configure the toggle based upon which option is selected. This is an extremely powerful tool, but it requires careful consideration and testing to ensure that the re-configure is consistent and doesn’t break the experience of a large percentage of users.

When rolling out a release many teams choose to test the toggle configuration that they intend to go live with, including any toggles that are flipped Off and any toggles that are flipped On. This helps to ensure that any new behavior will be enabled if the toggle is flipped On and that any legacy behavior will be disabled if the toggle is flipped Off.

It is also a good idea to test the fallback toggle configuration, which is generally a toggle that is flipped Off with all other toggles flipped On. This will help to prevent surprise regressions when the release goes live. This technique is sometimes referred to as Champagne Brunch, and it can be very helpful in ensuring that a release is consistent with the intended configuration. It is also useful for avoiding surprises when making changes to a production environment.