A toggle is a control that allows users to update their preferences, settings, and other types of data. When used correctly, toggles make it easy for users to see how their data changes and take the necessary action. However, when a toggle is misdesigned, it can create confusion or even a frustrating experience for users.

While there are many ways to implement a toggle, it’s important that the design and implementation are accessible to all users. This includes those with limited vision, color blindness or other visual impairments. Additionally, it’s crucial to provide clear, direct labels and utilize visual cues that are consistent with standard user interface design.

Generally speaking, toggles should be used to change an existing state rather than to introduce a new feature. This is especially true for toggles that allow users to modify pre-existing values. However, there are some situations in which a new toggle might be necessary to add to an application. For example, a new toggle might be necessary to implement a new form field for collecting contact information.

One of the most common uses for a toggle is to act as a circuit breaker in your application during high-latency periods. By enabling and disabling features in your application during these times, you can prevent bugs from spreading or causing a complete system failure.

Additionally, a toggle can also be useful for feature experimentation. By putting a new feature behind a toggle you can test how it’s received by a portion of your user base before rolling it out to the entire audience.

Toggle configuration is often stored in static files, which can be a pain to manage at scale. In order to avoid this issue, savvy teams are increasingly moving toward centralized toggle configuration stores. These typically reside in an application DB and have a UI where product teams, testers, and other stakeholders can view and modify the toggle’s state. By storing configuration in this manner, you’ll have the flexibility to roll out/back features quickly and ensure consistency across your fleet of servers.