What Is a Toggle?

Toggle is a user interface element that allows users to update preferences, settings, and other types of information by selecting one of two opposing states. When designing toggles it’s important to provide clear labels, use standard visual design elements, and deliver immediate results.

The word toggle can be applied to both software and hardware switching functions. For example the caps lock and num lock keys on a keyboard are toggles that enable or disable certain functionality. The same concept can be seen in most options menus found throughout software applications. When a toggle is pressed it turns a particular function on and when the same button is pushed again the function is turned off.

Savvy teams understand that every feature flag has a carrying cost and seek to keep that inventory low by only introducing new features via toggles when necessary. To that end many teams also create a process for tracking and removing toggles when they are no longer required. In some cases teams add a toggle removal task to the team’s backlog and others put “expiration dates” on their toggles so that they are automatically removed when they are no longer needed.

When a toggle is used to introduce new behavior it’s important to test all toggle configurations in order to ensure that the desired behavior is implemented correctly. This is typically done by testing the toggles in a live production environment with both the default and new configurations flipped on and off. Some teams also recommend that they test their toggles in a fallback configuration which will be enabled if the toggle is flipped off to avoid surprise regressions.

As with any type of user interface element it’s important to understand the limitations and constraints of toggles when designing them. For instance, it’s important to limit the number of times a toggle can be clicked in a short period of time because doing so increases the risk of accidental clicks and misinterpretations. It’s also important to consider the effect that color can have on user perception when designing a toggle. For example, in a study where four toggles were tested with the same functionality but one was portrayed in a darker and more pronounced color than the other the result was that the toggle which displayed a dark color performed worse than the other three.

Another common type of toggle is the Experiment Toggle which can be used to perform multivariate or A/B testing. This is accomplished by configuring a Toggle Router to consistently send a given user down one codepath or the other based upon their cohort. This is often used to make data-driven improvements to things like the Call To Action text on a button or the purchase flow of an ecommerce application.

A final point is to be careful when using toggles in situations that require a long delay before the system updates (e.g. a long form where other types of checkboxes are present). In these types of scenarios it may be better to use a separate button to request the information instead of relying on a toggle.