Toggle is a switch that has two positions, on and off. As a verb, it means “to alternate or shift between two states.” For example, you might toggle between screens as you video chat with two friends at once.
In software, toggles are used for a variety of purposes, such as enabling or disabling features and preferences. They are especially useful for allowing users to update settings or make changes quickly and with minimal impact. When implementing toggles, they should be easy to understand and clearly labeled as such. They should also be designed to appear as sliders and use visual cues to signal state change, such as movement and color.
Depending on the size and nature of your system there are many ways to manage and store toggle configuration. Some of the most basic approaches involve hardcoding a toggle’s state into an application’s source code using techniques like commenting or a preprocessor’s #ifdef feature. While this type of hardcoding is a good way to limit the number of toggles in a release it is not a very flexible approach. For instance, you would need to re-deploy your app in order to flip a toggle and this can have a significant effect on the cycle time of your validation tests, which is important for ensuring consistency in the user experience.
Another popular method for managing toggles is to store them in a dedicated toggle DB. This can be a more dynamic solution but it comes at a cost. The overhead of managing the DB is often high and it can be difficult to ensure consistent management across multiple environments. Some teams also find it challenging to track the history of a toggle as it moves between deployments in this type of system.
For these reasons, savvy teams tend to avoid managing toggles via a centralized DB and instead choose to store them side-by-side in an existing application DB alongside other source code artifacts. In addition, they will build-out some form of admin UI that allows product managers, testers and system operators to easily view and modify toggle configuration. Savvy teams will also be proactive in removing toggles that they no longer need from their releases. This is usually a separate task from the initial creation of a new release and some teams even create “expiration dates” for their toggles to remind them to remove them on a schedule.