In software and hardware toggle switches are a common way to switch between two functions. For example, keyboard keys like Caps Lock and Num Lock are toggles that turn a specific function on or off.

Togles are also a great tool for changing system settings and preferences. When used consistently, toggles are easy to use and provide immediate results.

Labels are essential to a toggle’s design, and must be clear. They should describe the option the toggle controls, and what state the toggle is in right now.

Colors are important for signaling a state change, and should be high-contrast. Low-contrast colors can be confusing for users, especially if they’re from a different cultural background.

Toggles should have state descriptors next to them, such as “On” and “Off.” This is especially true for toggle switches that are located in the bottom half of a screen.

Feature Toggles are often hardcoded into static files, but this can become difficult when you have a large number of toggles in your application. Fortunately there are a number of ways to manage toggle configuration more dynamically.

The most effective approach is to have a distributed configuration store in place. This makes it easier to modify toggle configuration across a fleet of servers and ensures consistency. However, there is a cost to this approach: toggle configuration has to live side-by-side in source control, making it harder to quickly deploy toggle configuration changes in a release.