A toggle is a small user interface element that allows users to easily update their preferences, settings, or content. Toggles typically convey their state to the surrounding context via an icon and use color to distinguish their current status. They also change their appearance based on their current state. Toggles are a great choice for user-interface elements that have mutually exclusive states – on or off – where a clear visual cue is needed to help users identify the current state of a system.
Toggles can be a powerful tool for building at startup speed, but it’s important to keep in mind that they must be consciously deployed and managed. They can quickly get out of control if you’re not careful. Toggle configuration is typically stored in static files, which is fine for a few releases, but becomes cumbersome once your team reaches a certain scale. Modifying these files can be difficult and inconsistent, and ensuring that every server has the same configuration across a fleet of servers is even more challenging. Many organizations decide to move their toggle configuration into some type of centralized store or database to simplify management and ensure consistency.
The term toggle has a variety of meanings, depending on the context in which it is used. Historically, it referred to a pin passed transversely through a hole or loop in a rope or chain to bind it temporarily. More recently, it has come to refer to a switch that can be placed in either an on or off position. It can also be used to describe switching between two different settings or programs (for example, “I’m toggling between the baseball game and the news.”
A common application for toggles is for A/B testing. Our ecommerce company, for example, may want to test whether algorithm B improves their conversion rates over algorithm A. To do this, they create an experiment toggle that splits the users of their configurator into two cohorts. The toggle routes each cohort down one of the two algorithms, and after a period of time they can analyze their results to determine which algorithm is more effective.
Despite their power, it’s important to avoid using too many toggles, especially when it comes to setting or preference options. This can be confusing for the end user and it will create a backlog of maintenance work for your team. It is also important to make sure that your toggles have a clear purpose and don’t overlap with each other.
Whenever possible, rely on other user-interface elements, such as checkboxes and radio buttons, rather than toggles. These user-interface elements are more readable than toggles, and don’t rely on color alone to communicate their state. Color is a weak signal that can be misinterpreted due to varying cultural and societal perceptions of meaning. For instance, the color red can be misleading to some users because they associate it with stop signs or traffic signals. It’s also important to note that WCAG guidance 1.4.1 states that “Don’t rely solely on color to convey meaning.” Using visual contrast, clear labels, and standard UI icons is better for accessibility than using toggles.
