Toggle is a term used to describe switching back and forth between different settings or programs. The term is also often used to describe a physical switch, such as the ones on keyboards or on hardware devices.
The most important thing to remember about toggles is that they are a way to control the behaviour of a piece of software. That means that when a team is writing an application they should always consider how their Feature Toggles might affect the behavior of their product in both the expected and unexpected ways. This is why a savvy team will test their toggle configurations with all of them flipped On and will also test their fallback (expected) toggle configuration with all of them flipped Off.
It’s worth noting that this type of testing is particularly critical when implementing a system which uses feature flags to perform multivariate or A/B tests. This is because a failure to understand the implications of a toggle-only configuration could have a detrimental impact on the cycle time of your validation process and on the all-important feedback loop which CI/CD enables.
The most common use of toggles is to change the state of a software function, such as turning Airplane Mode ON or OFF. In most cases this is the right control to use because it gives users the power to alter an existing functionality in a straightforward way which doesn’t require any other form of input or visual feedback. However, in some cases it might be more appropriate to use a
