A toggle is a switch that can be placed in one of two positions, either on or off. They are often used to control things like screen settings or video conferencing features in applications and hardware. They also appear in most options menus. The term toggle is also used to refer to hardware switches such as the Caps Lock and Num Lock keys on keyboards that allow the user to turn on or off corresponding functions.
Toggles can be confusing if the current state is not well understood, but there are ways to make them easier to read. For example, designers commonly use colors to help convey the current state of a toggle (e.g. green for on, red for off). However, color is not the only option and should be carefully considered with regards to accessibility. For example, 8% of male users have red/green color blindness so relying exclusively on the use of colors for toggle states can be difficult for those users to understand. Consider using a combination of colors and text to communicate the current state of a toggle.
Savvy teams view their Feature Flag inventory as a resource with a carrying cost, and they are proactive about removing toggles that are no longer in use. Some teams even create a backlog item for every new toggle and put expiration dates on them to ensure that they don’t stick around forever.
Toggle configuration can be managed in a number of ways, from static files to dedicated admin UI. The latter is most common and provides the ability for system operators, testers and product managers to view and modify toggle configuration in a robust and consistent manner. Toggle configuration that is managed via code comments or a preprocessor’s #ifdef feature does not provide this capability and requires a manual process of rolling out changes to the application in order to flip toggles. This is inefficient and can have a negative impact on the cycle time of your validation process.