Toggle is a control that lets users update settings, preferences, and other types of information with the press of a button. When used well, toggle switches make the user experience clear and efficient. Toggles should always have direct labels and be accompanied by a visual state indicator to avoid confusion. In addition, they should be limited to two possible states so that users can immediately determine whether the toggle is on or off.

Toggles are commonly used in technology, computing, programming, and communications to provide a way for users to quickly switch between different settings or modes. For example, a toggle might be the preferred control for changing a system’s “Airplane Mode” setting on mobile devices. A toggle is also a useful alternative to a checkbox when adjusting settings for which a yes or no answer is required because it takes up less screen real estate.

When using toggles, it is important to remember that the color red can be a cognitive cue for many users to “stop” and evaluate an action. It is therefore best to avoid red for toggle switches and instead opt for a color that signals a neutral or positive state (such as green, blue, gray, etc.). It is also important to consider societal and cultural factors when selecting a color for a toggle, as some colors may have unintended meanings in some cultures.

Generally, it is most efficient to implement toggles as dynamic properties in the codebase rather than as separate files. This reduces the number of times that the toggle’s value is fetched from a database, which can be expensive and slow for production systems. Similarly, it is often easier to debug and test toggles when they are inline with the rest of the code than when they are in their own file.

The disadvantage of this approach is that it is difficult to change a toggle’s state once it has been committed to the source code. It’s a good practice to use this technique only when the feature is expected to be stable for a long time and not to add it to new features that might be rolled out at some point in the future.

To minimize the impact of toggles on performance, it is recommended that teams limit the number of toggles in their codebase and remove any no longer needed flags regularly. Some teams even go as far as to put “expiration dates” on their toggles to prevent them from becoming part of a future production release. To further ensure that a toggle is not accidentally removed, savvy teams also write tests that verify how the production environment will perform with all the flags flipped on and a small set of tests that perform the same test with all the toggles flipped off. The latter test provides an early warning for potential regressions.