A toggle is a switch that is used to enable or disable features in technology devices and software applications. This type of switch is often found in everyday tech products to control things such as WiFi or Bluetooth(r). In software applications, toggles are used to enable or disable a feature, change an existing feature’s state, or configure an aspect of the application.
In many cases when you use a toggle to configure an aspect of your product you are using what’s called a “Feature Flag”. A Feature Flag allows you to dynamically re-configure specific service instances at runtime based on some criteria. This can be a powerful tool but it comes with a cost as you have to manually deploy the configuration into a testing environment. This can lead to an increased cycle time for validation and slows down the feedback loop that CI/CD systems provide.
Ideally the toggle configuration would live side-by-side with the production code in source control. This makes it easy for teams to verify that a release has not changed the toggle configuration and that they can easily recreate the previous toggle state. The drawback to this is that the ability to re-configure toggles at runtime can be difficult if you are managing a large number of them. To help with this problem most organizations will implement some sort of centralized management system for their toggle configuration which may be in the form of a database or even a config server which sits alongside the application.
When designing a toggle switch it is important to ensure that the visual cues are clear enough for users to understand what they will do when pressed. This is especially important when designing a toggle that will impact user experience. The color used to represent a toggle’s state should be high-contrast so that users can differentiate between On and Off. It is also a good idea to include the word On or Off next to the switch to further reinforce its function.
Toggle switches are commonly used to allow users to choose between different themes for an application. However they can be adapted to a wide variety of uses such as changing the background color of an application, enabling or disabling chat, and adjusting call-to-action language.
Another very common use for Toggles is to perform multivariate or A/B testing. This is done by creating a Toggle Router that consistently sends a given user down one or the other code path based upon the cohort they belong to. Over time the system can be analyzed to determine which codepath yields better performance. This can be a great way to quickly test new features that you might not want to put into the main product without a longer development and testing process. This is particularly important in more agile development approaches such as Scrum, Kanban, and SAFe. In more traditional waterfall development processes these new features would be put into code branches which then need to go through a lengthy regression testing and QA process before they could make it into the main product.
