Toggle is an on/off switch (or slider) that allows users to update preferences, settings or other kinds of state. When used well, toggle switches are an effective user-interface component that can provide immediate results and reduce the amount of clicks required to change a setting or preference.
Toggles are also an important tool for performing multivariate or A/B testing. Essentially by configuring an experiment with multiple codepaths and then running it against different cohorts of users we can determine which version of the system performs better.
In software development the word toggle can be used to describe all kinds of switching, from simple on/off like the caps lock or num lock keys on your keyboard through to complex multi-state configurations such as opt-in and opt-out features found in most computer applications.
When designing interfaces that use toggle switches it’s important to consider how the switch looks and how it is labeled. Ideally the switch should be easy to read with clear and direct labels that tell what will happen when the toggle is flipped on or off. It’s also helpful to use color for the switch state and consider societal and cultural contexts for how that choice may be perceived.
Savvy teams look at their Feature Toggle inventory as a type of inventory that comes with a carrying cost and seek to keep it low by being proactive about removing toggles that are no longer needed. This can be done using a variety of techniques from refactoring the code to using a backlog item to track when a toggle should be removed.