Toggle is a simple UI control that enforces two mutually exclusive states, on and off. Toggles are used when users update preferences, settings or other types of information – they deliver immediate results and provide clear contextual cues on what state they are in.

It’s important to keep in mind when designing toggle switches that they should always be accessible. This means ensuring that they are not hidden, that their labels describe what the switch will do and that they don’t rely on color alone to convey meaning (see WCAG 1.4.1). This is particularly important when using a toggle with a dark background, because the contrast between the dark background and the light foreground can be difficult for some users.

Another consideration is the use of toggles with multiple possible state combinations. This is common when we have multiple different options to implement and need to verify the effect of each on a specific subset of our user base. To avoid this problem it is helpful to separate the UI into different sections with one for each possible state. This allows us to test each option separately by having a random selection of users see the UI with one state and then compare the results of that to a group of users seeing the UI with the other state.

Toggles are also a popular tool for performing A/B testing, where we send different cohorts down different code paths. We can track the outcomes of these experiments and then re-configure the toggles to deliver the best version of the feature to the remaining users.

We’ve explored some of the most common uses for Toggles in this article, but there are many other ways they are implemented. Some examples include Experiment Toggles, Permissioning Toggles and Champagne Brunch Toggles (where a feature is only exposed to a very specific set of premium users).

There are several approaches to managing the configuration for a toggle, from the use of static files through to more sophisticated solutions that require the application of some sort of preprocessor. We typically recommend moving to a solution that provides a centralized store for toggle configuration. This enables us to make changes at scale and ensures consistency across all environments and devices. It also means that when we decide to re-configure a toggle it can be done with minimum disruption to the rest of the system.