What Is a Toggle?

A toggle is a switch that has two positions, either on or off. It is an essential element of user-interface design and is used to update preferences, settings, and other types of configuration. When it is well designed it minimizes scrolling, is easy to use, and delivers immediate results. Toggle switches should be clearly labeled and should utilize visual cues such as movement and color to convey their current state. The color of a toggle should be high-contrast to ensure that it is easily seen, and designers should consider societal and cultural context when choosing colors for toggle switches.

In addition to being an important UI component toggles can also be useful as a navigational tool when designing websites and applications. Collapsible toggles such as accordions can help users find the information they need without scrolling through long pages and navigating complex navigation systems. Similarly, toggles can be used to make long article content easier to read and understand by hiding less-important sections of an article.

The term toggle is also used in software engineering to describe the process of enabling and disabling features for individual users. This is a common practice for testing and experimentation on production software, but can also be used to change default behavior or to enable feature access for specific groups of customers. Savvy teams view Feature Toggles as inventory that comes with a carrying cost and seek to keep this inventory low by diligently removing toggles when they are no longer needed. To this end they often create “expiration dates” for toggles that are no longer needed and set up automated tests to remove the expired toggle from their test environments.

There are a number of approaches to managing the configuration of Feature Toggles, from simple comment-based hardcoding through to more sophisticated systems which manage the state of a toggle on a per-request basis. As the use of Feature Toggles becomes more widespread many teams move from using static files to some type of centralized store, typically an existing application DB. This is often accompanied by the build-out of some form of admin UI which allows system operators, testers and product managers to view and modify the configuration of a toggle.