A toggle is a switch that has two positions: on and off. It can also be used to bind something temporarily, like the cordlock toggle that stops a drawstring.

When designing UI with toggle switches, remember that they represent a tradeoff between flexibility and clarity. A toggle switch should be simple to understand and use, with direct labels and clear visual cues for state change. Ensure that the color and movement of the switch clearly communicate its state. Color can be especially important for toggles that are configured to be used by users from different cultures or with varying degrees of cognitive ability.

Often, a toggle will be used to make an option available to users that would not otherwise have it (for example, adding a call to action on a form field). This is sometimes referred to as a Canary Release or Champagne Brunch. Other times it will be a way to perform multivariate or A/B testing with a targeted cohort. For this type of testing, the toggle will be configured to consistently send the user down one codepath or another based on their cohort.

Savvy teams know that each toggle comes with a carrying cost and are proactive about removing them from the system when they are no longer needed. To this end, many teams will have a backlog item for every new toggle that is introduced to the system and even put “expiration dates” on some of their toggles so they are automatically removed from production after a certain amount of time.