A toggle is a switch that allows you to manage the state of something. Generally speaking they have two states: On and Off. It is common to use them in settings menus and elsewhere on software where you need to control things like the Caps Lock and Num Lock keys. They also are commonly used for A/B testing and other experimentation where we want to test the impact of a particular change to the overall experience.
Traditionally a toggle is implemented as a button with an on and off label. This is fine but it comes with some challenges. First, a button that just says on/off doesn’t help users understand the state of the toggle. Users need to know a visual clue that the toggle is currently on or off. It is common practice to add a second icon or some other cue that makes it clear the toggle is in a specific state. The issue is that this increases the complexity of the UI and can cause confusion.
Another challenge is that toggles require extra code to manage their configuration. Often you end up with a series of if-else statements that violate clean code principles. Fortunately, more and more teams are moving to systems that make it easy to store toggle configuration in some sort of centralized database (usually an existing application DB) or through some sort of admin UI.
Finally, it’s important to consider the impact that a toggle has on your testing and deployment process. A toggle should be flipped off for releases and a team needs to have some way of ensuring that it doesn’t break the build/test cycle. This may mean adding a toggle removal task on the backlog for each release or even creating “time bombs” in the form of flags that will fail a test if they are not flipped off in time for a deployment.
