A toggle (or toggle switch) is a control that has two states: on or off. It’s used in electronics and software to enable or disable functionality. In user interfaces toggles are often preferred over radio buttons because they take up less space and allow for clear visual cues to communicate status. However, choosing the right visual clue is not as simple as it might seem and can do more harm than good when not done well.

Toggle is an important tool for a team to use, but it’s one that comes with a carrying cost and savvy teams seek to keep the inventory low. Many teams add a task to the backlog to remove any Feature Toggle that is no longer needed as soon as it’s introduced and others even put “expiration dates” on their Feature Toggles so that a release can fail if a toggle has not been removed by an appropriate date.

When testing a toggle it’s also a good idea to test the toggle configuration which is expected to be live in production. This includes testing the toggles you intend to release flipped On and the fallback configuration which is enabled when those toggles are flipped Off. This is a great way to avoid surprise regressions in your production environment and will ensure that you can confidently test the behavior of new features without having to worry about changing toggle state in previous releases. Ideally you would do this for all toggles but it’s especially important for more dynamic Feature Toggle decisions.