A toggle is a control that allows the user to update preferences, settings or other types of information. Toggles are often preferred for these types of updates on mobile because they take less screen estate than two radio buttons and deliver immediate results. Like all controls, however, they must be used carefully and in the right context. If you find yourself designing a user interface where toggles are needed make sure they are clearly labeled, are easy to understand, and use standard visual design principles.
Toggle can also refer to hardware switching: for example the Caps Lock and Num Lock keys are toggle switches that allow the user to turn on or off specific functions on their keyboard. Similarly, toggles can be found in options menus on many software applications where the user is able to switch between different functionality options by toggling the switch for each one.
Often times a Release Toggle will be short lived; for example the toggling decision may only last a week or two (although some product-centric toggles may be needed longer). A good practice is to create a task on your team’s backlog to remove the toggle at the end of each release cycle. This will help keep the inventory of Feature Toggles manageable and prevent accidental or inadvertent changes to production code.
A Feature Toggle should only be flipped when a new change is to be made available to users. Leaving a toggle flipped for an extended period of time is risky, and can have unforeseen consequences for the product. For this reason, a good practice is to ensure the toggle is only ever flipped by an experienced member of the development team.
When using toggles be careful to select a consistent color for each state; this will help users to understand the current state of a toggle. In general, high contrast colors will be easier for users to read than low contrast colors. Additionally, it is important to consider societal and cultural implications when choosing states for a toggle; for example, using red to indicate an On state could be counterintuitive for some users who associate the color with stop signs or traffic lights.
As your system scales it can become difficult to manage the configuration of toggles via static files. For this reason it is recommended that you build out some type of centralized configuration system that can be used by product managers, testers and developers to modify the state of a toggle. Ideally this will be done through an existing application DB and accompanied by some form of admin UI. This can help reduce the time it takes for a developer to re-deploy a test environment after modifying a toggle and will also speed up the feedback loop for testing and validation processes.
