A toggle is a switch that has two positions, on or off. You see them in every hardware control that has a on-off option like your keyboard’s Caps Lock or Num Lock keys, or the options menus of most software applications. They’re also used in the browser to quickly switch between various streams of information or maps in a web page.
It’s important that toggle switches are easy for users to understand what state they’re currently in. The color of the toggle should be high-contrast to ensure that this is the case. Additionally, it’s a good idea to use label text that describes what will happen when the toggle is activated. This will help users avoid confusion and make sure they’re always aware of what they’re enabling or disabling.
Toggle switches are often used for multivariate testing (A/B testing) where you can compare the effect of two different codepaths on an individual user. The advantage of this is that you can see which path had a positive impact without having to ask the user to interact with another page and click on a Save or Confirm button.
While static file-based configuration is preferable for most scenarios, there are some cases where a more dynamic approach to Feature Toggle configuration may be required. One such situation is when it’s necessary to share the same configuration across a fleet of servers (e.g., an Ops Toggle). When this is the case it’s a good idea to implement some form of admin UI which will allow system operators, testers and product managers to view and modify all of the Toggle Configuration.