In software, a toggle is any option item that can be marked on or off. This can be a button or slider, and it can also be an element of a menu item.
A toggle is a simple user-interface component that can make a big difference in how users interact with your product or site. Toggles help users update preferences, settings, and other types of information. In order to be effective, toggles should provide direct labels, use standard visual design, and deliver immediate results.
The word toggle comes from the French verb toggler, which means to switch or toggle. It is a common idiom for switching between different actions, such as when you turn your caps lock on or off.
Toggles are commonly used in software and hardware, as they allow the user to decide between two opposing states — on or off — using a single switch. This is similar to the way a mouse works with its buttons.
Definition
The simplest way to understand what a toggle is in general computing is that it is a switch that has only two possible outcomes, A or B. It is most often used in option lists where the user can mark a particular setting or behavior as either On or Off.
It is also a term for a fastener that binds together something by passing a pin, bolt or rod through the eye of a rope. Toggle rail, a device that attaches to a frame for strengthing it, is another popular term.
Feature Toggles
A toggle is a type of Feature Flag that is usually not part of a normal release process, though some teams have a longer-lived category such as Permissioning Toggles. When used as part of a process where features are only accessible to premium users, or based on user permissions, a Permissioning Toggle can be extremely long-lived.
In order to maintain the overall manageability of a codebase that consists of thousands of Feature Toggles it is important to be proactive about removing feature flags that are no longer needed, or that have been around for a long time. This can be done by introducing an expiration date for feature flags, or putting a task on the backlog to remove them if they are no longer needed.
Static Configuration
In general a static approach to managing toggle configuration is preferable but there are some situations where this approach does not work. One such scenario is the case of Ops Toggles where you may need to re-configure a feature flag dynamically on runtime. This is not ideal because it can require restarting an application or re-deploying artifacts into testing environments, which are both expensive and wasteful of cycle time.
