A toggle is a switch which has two positions, on and off. A toggle can be used to control things like brush size, paint drop-off and opacity on a painting application or to change the font on a webpage. It can also be used to perform multivariate or A/B testing by directing users down different codepaths. It’s important to remember that toggles are not always the best choice for every situation and they can sometimes be incredibly confusing.

Traditionally toggles are created using an HTML input> tag which can be configured to use different CSS classes depending on its current state. This approach has the benefit of being flexible, allowing developers to create a toggle for almost any type of input. However this flexibility can come at a cost as it can be difficult to manage, especially at scale. For this reason many teams prefer to use a more robust, dedicated toggle management system.

One of the most common ways to do this is by creating a custom plugin which can manage toggles and their configurations. This allows a team to keep its toggle inventory under control and make changes quickly and easily. This type of plugin is also ideal for extending the functionality of existing applications which already use toggles.

Another way to manage feature toggles is by hardcoding them into the codebase. This can be done through a variety of means such as commenting or using a preprocessor’s #ifdef feature where available. This approach has the benefit of ensuring that toggle configuration lives side by side with release configuration in source control but it is less dynamic than other solutions.

Once a team has managed to keep its toggle inventory under control it must then ensure that all tests are run with the expected toggle configuration. This typically means that the toggles which are set to go live are flipped On and the ones which are not are flipped Off. It’s also important to test the fallback configuration which is the configuration that would be in place if all toggles are Off. This will help to prevent a surprise regression in a future release where new or legacy behavior is enabled.

In addition to these general considerations there are specific issues which arise when working with toggle switches which require a little more thought. For example, it’s important to pick a good color scheme for toggles as they are known to be particularly confusing to some users. This is particularly important for accessibility reasons as it can be impossible to tell what state a toggle is in based solely on its current visual appearance. Similarly, the default text ‘On’ for toggles can be confusing to people with color blindness as it can appear as either green or red.

Finally, it’s vital that a team is proactive about removing toggles which are no longer needed. This can be as simple as adding a toggle removal task to the backlog for a release or more sophisticated by creating “time bomb” tests which will fail a release if the associated toggle is still present.