A toggle switch is a control that allows you to flip between two states or options. It is a common component in technology, computing, and programming. You can find toggles in everyday technology like smartphones, where you use them to turn WiFi or Bluetooth on and off. Toggles are often used in user interfaces to show or hide menus or sidebars in responsive web designs, or to change the display mode based on screen size.

The term toggle is also used to refer to a feature that is switched on or off via a feature flag in the codebase. The toggling decision can be based on many different conditions such as fitness test results, a setting in feature management software, or a variable provided by the config file. The toggle can also be triggered by user actions such as pressing the button or selecting an option.

While toggles are very useful and have a place in most applications, it is important to limit their scope. It is tempting to put large swaths of the application under the control of a complex series of toggles, but this can be confusing for the team and a nightmare to debug weeks or months down the line. It is much safer to choose one toggle to cover a single feature.

When designing a UI with toggles, it is important to keep in mind the WCAG guideline 1.4.1 – Don’t rely solely on color to convey meaning. While you can use colors to indicate that the toggle is on or off, it is best to rely on other visual cues such as movement and positioning. In addition, it is essential to clearly label the toggle switches so that the users can understand what each state means and what will happen when the switch is activated or deactivated.

Using toggles to hide sections and items in an article can be very helpful, especially when you are dealing with long articles that would otherwise be overflowing the page. This is especially true for pages that require scrolling to view all the content. To use the toggle, hover over a section or item in the presentation view of an article and an eye icon will appear. Clicking it will hide the section or item, and clicking again will make it visible.

The toggle is also useful for experimenting with features on a small number of users. For example, if you are testing which of two suggestion algorithms provides the best conversion, you can create an experiment toggle to split your production traffic into cohorts that see each algorithm. Once you have the data, you can remove the experiment toggle and roll out the preferred algorithm for all users. If you have a large user base, it may be difficult to get the data that you need to create an experiment toggle. In this case, you may need to use a Champagne Brunch or a Canary Release instead.