A toggle is an on/off switch that can be flipped either way. It is typically found in settings menus and almost any computing context where you have a set of options or preferences to choose from. A good example of this is a keyboard’s Caps Lock and Num Lock keys which are toggle switches that enable different functions on the machine when pressed.
There are a number of ways that teams manage feature flag configuration ranging from approaches which are relatively simple but less dynamic through to others that are more complex but provide more sophisticated runtime re-configuration capabilities. Regardless of the approach it is important to ensure that toggles are clearly labeled as being On or Off, and that the visual cues used to represent their state make it obvious to users that they can see which way they are currently configured.
It is also wise to ensure that your team tests the toggle configuration that you expect to end up in production in order to prevent regressions from unexpectedly occurring in a release. In addition, savvy teams are proactive about ensuring that their feature flag inventory is always trimmed by adding a task to the team’s backlog to remove a toggle once it has been unused for a while. Some teams even go so far as to add an expiration date to their toggles which will cause the test to fail if a toggle is still deployed after its expiration.