A toggle is a small piece of wood or plastic that is sewn to something such as a coat or bag, and which is pushed through a loop or hole to fasten it. In computers and some other machines, a toggle is used to switch between functions.

A toggle can also refer to a piece of metal that is attached to a frame, allowing it to slide along a track to position the rail at different heights.

In web design, toggles are often used as a control that allows users to update preferences, settings, or other types of information. When designing toggles, it’s important to consider the cognitive issues that can arise from their use and ensure that they are clearly labeled, visually recognizable, and deliver immediate results.

There are two things that are particularly problematic about using toggles in user interfaces: their color and their reliance on a single state descriptor (on/off). For example, if a toggle uses the colors green and red to signal its states, then 8% of male users have red/green color blindness, making it difficult for them to determine whether or not the toggle is on or off. To avoid these issues, designers should use high-contrast color schemes, evaluate societal and cultural implications for their audience, and use clear state descriptors (like On and Off) to make it easy for users to understand what they’re seeing.

In coding, toggles are similar to feature flags, but they are typically long-lived and semi-permanent, and they are often used in conjunction with more complex decision trees that act upon many different variables. Toggles are generally more stable than branches, so they can be a useful tool for developers in ensuring that their codebase is working as expected.

When a dev team decides to add a new feature, they can create a release toggle in their master codebase that flips the feature on or off for a small set of conditions. This allows them to test the feature without affecting the entire production branch. Once the team is happy with its performance, they can push the feature to production and stop using the toggle.

The best name for a toggle is one that provides the most valuable information to anyone who sees it in an error message. A good name identifies who wrote the toggle, how long it’s been around in the codebase, and what its purpose is. By following this practice, your codebase will be easier to manage and maintain, and your users will have a better experience using your website or application. Moreover, it will help you maintain a healthy codebase that can meet the needs of your customers for years to come.