A toggle is a control that allows users to switch between two states. It is usually a button that can be clicked to turn something on or off. There are many different types of toggles. For example, a radio button or checkbox may be used as a toggle. It is important to understand when a toggle should be used, and in what situations. This will help you avoid making mistakes that can lead to confusion for your users.
Using Toggles
A common use of toggles is in order to perform experimentation or split-testing on your website or app. Typically, the toggles are used to change specific aspects of the application such as the purchase flow in an online ecommerce system or the Call To Action wording on a button. By applying these experiments or split-tests, you can gather data and determine which configuration of the system is the most effective.
This type of testing is also known as Multivariate or A/B Testing. A toggle is used to send a given user down one codepath or another and then record the behavior of that user, comparing the results of each path. Over time you can then make data driven optimizations to your site or app to improve the performance of it.
While this type of testing is useful, it does have drawbacks. Specifically, it is difficult to replicate the exact same testing conditions on each of your live servers. This can be problematic, especially when you are testing on a large scale. As such, many organizations move their toggle configuration away from static files and into some form of centralized store. This is often an existing application DB. This change is often accompanied by the build-out of some sort of admin UI which allow systems operators, testers and product managers to view and modify Features Flags and their configuration.
Other applications for toggles include things like security settings. For example, an admin can create a toggle that allows them to hide certain parts of an article from non-admin users. This allows the admin to test changes without having to publish them to everyone.
Toggles are also used to support agile development models. Rather than writing a new feature on a branch and going through a lengthy test and QA process, developers can create a toggle in the production codebase that leaves that new feature active until it is ready to be rolled out. This can be done even for features that require significant coding.
A final note on cognitive usability: While toggles work well in most cases, they do have some problems when it comes to accessibility. Using colors to convey states is problematic for users with color blindness. This is why guidance from WCAG 1.4.1 is to not rely on colors to convey meaning and use alternative cues like text or icons. In addition, users with motor impairments might find it difficult to click on a toggle if they cannot reach the button or are unable to press it.
