Toggle is the term for a hardware or software switch that turns a feature on or off. It’s common to see toggles in keyboards, mobile phones, and other devices to control various functions like airplane mode. Similarly, toggles are a preferred option in settings menus because they take up less screen real estate than two radio buttons.
Typically, toggle switches look like sliders and utilize visual cues (movement and color) to avoid confusion. It’s also important to make sure that toggles have clear labels so users know what the switch will do when flipped on or off. It’s not a good idea to add the label first and then use a different icon for the toggle because it makes it difficult for users to understand which state the switch is in without reading the label.
Savvy teams view the Feature Toggles in their codebase as inventory which comes with a carrying cost. As a result, they seek to minimize the number of toggles by actively removing them when they are no longer needed. Some teams have a practice of adding a task to the backlog whenever a toggle is flipped Off for the first time and others create “expiration dates” on their toggles that will cause automated tests to fail if a toggle hasn’t been re-activated within a certain period of time.
Toggles are great when it comes to changing system configurations but they don’t work very well in situations where users need to answer a question or make a choice. For example, if the user is deciding whether to accept or reject cookies, it’s much better to use a checkbox than a toggle because a toggle only has two options: ON and OFF. Toggles are also not a good choice in forms where the user must click a Save or Confirm button for the changes to take effect.
It’s also not a good idea to rely solely on color for the indication of status since this doesn’t play well with some users. For example, 8% of men have red/green color blindness and they would be confused if green meant on and red meant off. It’s best to rely on color in combination with other signifiers and always provide a description of the current state of a toggle.
Managing Toggle Configuration can become cumbersome at scale and many organizations will move to a more dynamic solution such as a centralized config DB or an application service which allows for per-request re-configuration of toggles. In some cases this will be accompanied by a more sophisticated admin UI for product managers, testers and systems operators to manage toggles in a more controlled fashion. Using static files for this purpose is fine until you hit a certain level of complexity and the process of modifying them becomes cumbersome or error prone.
