The toggle is a common feature in many everyday technology devices. For example, keyboards have toggles that allow you to enable and disable functions such as Caps Lock or Num Lock. Similarly, toggles can be found in software applications to control the appearance and functionality of menu items.

Feature toggles are used for A/B testing, enabling your engineering team to experiment with new features in a real-world environment before they roll out to your entire user base. Toggle-based A/B testing helps reduce the risk of releasing a new feature that your users won’t embrace.

Additionally, toggles can be used as a circuit breaker for your application, temporarily disabling non-essential functionality during times of high latency or other critical issues. This prevents users from experiencing any unexpected or undesirable behavior and allows you to troubleshoot more effectively.

Because toggles rely on visual cues to communicate their state to users, they must be designed with accessibility in mind. It’s crucial to use proper labeling and animation to ensure that toggle buttons are accessible to users with disabilities. Additionally, it’s a good idea to stick with a consistent convention for toggle semantics, where existing or legacy functionality is enabled when a toggle is flipped On and new or future functionality is enabled when a toggle is pushed OFF. It’s also wise to test your toggle configuration in production with both the expected toggle state and a fall-back configuration where all toggles are flipped Off.