A toggle is a small piece of wood or plastic that is sewn to something like a coat or bag, and then pushed through a loop or hole to fasten it. Toggle also refers to software and hardware buttons that allow you to switch between functions. For example, your computer’s Caps Lock and Num Lock buttons are toggle switches that enable you to switch between two different functions.
On a web site or app, toggles help users update their preferences, settings, and other types of information. When used properly, toggles are easy for visitors to understand and provide immediate results. For best practice, toggle switches should be clearly labeled and be designed to use standard visual design and color cues. Additionally, designers should be mindful of societal and cultural implications when using toggles to signal state change.
While a toggle can be an effective way to provide users with the ability to control the behavior of an application, it’s important to understand that toggle configuration must be managed and maintained over time. For this reason, many teams choose to build out a system of toggles and their configuration into some type of centralized store, often an existing application DB. In this approach, a team can easily view and modify the toggle configuration over time to ensure consistency across the platform.
When a toggle is flipped on it allows new behavior to be enabled and then when the toggle is flipped off the old behavior remains enabled until the toggle is re-flipped on. For this reason, it’s important to test a release with all of its toggles flipped On to prevent unexpected regressions in production.
Some teams opt to hardcode the toggle configuration within their code via commenting or the preprocessor’s #ifdef feature. This approach is problematic because it doesn’t allow for dynamic in-memory re-configuration of a toggle. Additionally, this method can become cumbersome when the toggle configuration is large as it’s difficult to maintain and verify the code.
Other teams choose to implement a more advanced toggle management system by building out an administration UI that provides a visual representation of the configuration and enables team members to dynamically re-configure individual service instances. This solution is typically more performant than the commenting or preprocessor #ifdef approaches and provides a more reliable and robust configuration management solution. In addition, this type of system is easier to integrate into a continuous integration/continuous deployment (CI/CD) process as it doesn’t require re-deploying the artifact to change its toggle configuration. However, this more sophisticated approach is still limited in scope and requires a lot of development resources.
