Toggle is a user-interface component that allows users to update their preferences, settings, and other types of information. When used well, toggles provide a clear, consistent way to make changes without impacting the existing experience of other users. However, toggles can be confusing when designed poorly, so it’s important to always evaluate context before implementing them.
Toggles are a common tool for doing things like changing call to action wording on a button or making other data-driven optimizations. Toggle configuration is often managed in source control with either a static commenting approach or an advanced (and somewhat complicated) approach that uses preprocessors to perform dynamic re-configuration at runtime. This makes it easy to see what toggle configuration is being used by a particular cohort and compare the results of different code paths to each other.
When using a static commenting or preprocessor-based approach to managing feature flags it’s generally best to only release the toggle configuration that you expect will go live in production. That way, it’s impossible to introduce new regressions in a future version. To further reduce the risk of surprise regressions it’s a good idea to also test the fall-back configuration, where all toggles you intend to release are flipped Off.
When designing toggles it’s important to remember that color is an important visual signifier for a toggle’s current state. As a result, it’s generally recommended to only use a contrasting color scheme and to consider cultural and societal implications when selecting colors for your toggles. For example, many users have red/green color vision deficiency and using the colors green and red to convey on and off states could be very confusing for those users.
