A toggle is a kind of switch that lets you set the behavior of something, often by changing its state. Toggle switches can be used for all kinds of things, from enabling and disabling features in your application to controlling how an API returns results to your users. They can be especially useful for testing or demonstrating new functionality, because they allow you to make changes without affecting everyone at once.

A common use case for feature toggles is to enable or disable a specific piece of content in an article at a moment’s notice. For example, you might want to hide the subscriber group containers and map boxes for a particular readership segment. Toggle settings for this can be found in the world configuration page, accessible from the gear icon and double gears on a post (more info here). You can also use toggles for visibility of individual items in an article. Just mouse over a container, and if it has the toggle setting checked, you’ll see an eye icon appear in the top right corner of the box. Click it to hide the content, and uncheck to reveal it. Note that this only applies to the current view of an article, so readers with other views (including article previews) will still be able to see the hidden content.

Another common use of feature toggles is as circuit breakers for a production application. If you have a major new release that’s going to cause some latency issues, you can use a toggle to temporarily disable the feature while you investigate and fix the problem. This allows you to roll out the feature to your entire user base without causing too much disruption, and it gives your team time to test and implement a fix before the issue becomes widespread.

In many applications, toggles are designed to be cognitively okay – assuming that the designer uses high-contrast colors and doesn’t rely too heavily on color alone to convey meaning. But there are a few considerations to keep in mind: color blindness is a real issue, so some designers use red as an on/off switch, and some users may associate certain colors with societal or cultural meaning.

The ability to quickly re-configure specific service instances is a powerful tool, and should be used sparingly. Ideally, only automated tests should use this feature, and the capability to manually re-configure services should be reserved for exploratory testing or debugging purposes. If you find yourself in the situation where it’s necessary to use toggles for manual configuration, be sure that it’s done in a controlled environment. Otherwise, you could end up creating a confusing and unnecessarily complicated interface that will be difficult to maintain. In a shared environment, it’s also important to make sure that you have a robust version control system in place to ensure that everyone is using the same toggle configurations. This will help to prevent confusion and reduce the risk of accidental configuration drift between different teams.