A toggle is a switch that can be activated to make something happen or deactivated to prevent it from happening. It is used in technology, computing, programming and communications to allow for a choice between two states or options. Toggles are commonly used in responsive design in web development to change a light or dark theme and can also be applied for A/B testing with cohorts.

The key thing to remember with toggles is that they are transitional by nature and should only be present for a short period of time. They should be rolled out, tested and then removed once the team is satisfied that they are stable. This way the risk of introducing a bug which breaks functionality is minimised. This is known as blue-green deployment.

It is important to use toggles that are clearly labelled with clear and direct information for both on and off states. This is to ensure that users can understand what each state means and how it relates to the other state. If a toggle is not well labelled, for example using a low contrast color to indicate an on state then it can become difficult for users to understand its purpose. It is also important to consider societal and cultural differences in colour meanings as not everyone will see the same meaning of a given colour.

It is also important to have a way to manage the configuration of toggles in a dynamic manner. This can range from simply commenting out the toggle in source code, through to more sophisticated approaches which rely on a preprocessor’s #ifdef feature or a remote endpoint to do the re-configuration at runtime.