In the context of software engineering a toggle is a switch that allows you to enable and disable functionality. Feature toggles are used in continuous development to test new features with a small segment of users before rolling out to all users. This practice helps avoid the cost of a failed feature release.

Generally speaking operation toggles don’t last much longer than a few days or weeks. Once a new version has launched with no issues you’ll typically retire the toggle. Permission toggles on the other hand can have a very long lifecycle – particularly if they are used as a circuit breaker for an application by disabling non-essential features during high latency periods.

Savvy teams view their feature toggle inventory as a carry-over from previous releases and they’re always looking to minimize the amount of toggles in their codebase. For this reason it’s common for teams to add a task to their backlog for toggle removal after each feature is rolled out. Some teams go even further and put “expiration dates” on their toggles to ensure they are removed when the time comes.

When designing a toggle it’s important to keep accessibility in mind. If a toggle has a fixed color like green for ON and red for OFF it can be difficult for users with visual impairments to distinguish one from the other. To improve usability for such users it’s a good idea to use contrasting colors or text descriptions to clearly differentiate the state of a toggle.