Toggle is a word that describes something that has two positions, on and off. It can also be used to describe the process of switching between different functions on a machine, like adjusting screen size when video chatting with two friends at once.
Toggles are heavily used in modern interfaces and can be thought of as glorified checkboxes. However, they can be confusing to users if not used correctly. Choosing the right visual cue is tricky because toggles do not contain the text on or off, which means they rely on other attributes to communicate their state. Generally, this requires an icon that clearly communicates its purpose and updating the appearance of the toggle based on its current state. Different platforms have their own style guidelines for toggles so it’s important to choose a platform-appropriate option.
Using toggles for features that are only ever exposed to certain cohorts is an excellent way to manage the complexity of multivariate testing (or A/B testing). Toggle switches are great for this because they can be flipped on and off at runtime to test the impact of codepath changes without having to redeploy an entire artifact into a production environment.
When a toggle switch is being used for this purpose it is also critical that we ensure it is accessible. A toggle switch that is purely graphical can often be difficult for users with visual impairments to read, particularly if it uses red as on and green as off. It is often recommended that a toggle switch should be marked up as a button, and use the aria-pressed attribute to indicate its state.