What Is a Toggle?

A toggle is a simple user-interface component that allows people to update settings, views, or other types of information. The toggle’s contrasting appearance in each state helps users determine the action it will take, and appropriate labels help further clarify this binary choice. When used effectively, toggles provide a smooth user experience and can make a large impact on the success of your app or website.

The word toggle has several meanings: as a verb, it means “switch or alternate,” for example when you toggle between screens during a video chat with two friends at once. The word can also be applied to hardware like a cordlock toggle, which stops a drawstring from unwinding. It can even be used to describe an on-off command, as in the Caps Lock and Num Lock keys on your keyboard.

Toggles are used in software to perform A/B testing, a technique which lets teams measure and compare the effectiveness of different codepaths. For each test, a cohort of users are sent down one path while another group is routed to the alternative. The results of the experiment are then compared and analyzed to identify the best paths forward. This process is known as Feature Flagging.

In some cases, teams may have many Feature Toggles in their codebase and must be proactive about maintaining the lowest inventory possible. Savvy teams will look at their Feature Toggle inventory as inventory that comes with a carrying cost and seek to minimize the amount of time and effort required to manage this inventory.

There are a few ways to implement a toggle in your app, depending on the context and your goals. In a general sense, the toggle should look similar to sliders and use visual cues to communicate its state. For instance, the switch should move as its state changes and use a clear color scheme to distinguish between active and inactive states. Additionally, the label should clearly describe what will happen when the toggle is clicked, and be easy to read.

For example, the label for a toggle that is meant to download content should be clearly displayed next to the switch. This will ensure that users know whether the toggle is set to download or not and can make an informed decision about how to proceed. On the other hand, if the toggle is meant to be used to cancel an ongoing download, it should be clear that it can only be cancelled when the switch is unset to download again.

Toggle configuration can be managed in a number of ways, ranging from a very simple approach which requires only hardcoding into the source code to a sophisticated approach that involves a preprocessor’s #ifdef feature. The latter approach is typically reserved for a few select use cases where it is necessary to dynamically re-configure the toggle’s state at runtime. For most other uses, a more straightforward approach is appropriate.