A toggle is a switch with two positions — On and Off. It is found in most settings, preferences, and options menus, including in software applications.

It is also used in hardware to refer to an on-off command for a specific function. For example, the keyboard’s Caps Lock and Num Lock keys are toggles that enable and disable those functions when pressed.

Toggle labels should describe what the control will do when toggled on; they should not be neutral or ambiguous. This is especially important when using low-contrast colors.

Colors are an important visual signifier for toggle switches, and should be high-contrast to avoid confusion. State descriptors, such as On and Off next to the toggle, are another good way to provide clear visibility of the system status.

A toggle should be designed to look like a slider, and use standard visual design principles and triggers to allow users to change the switch’s position. Toggle switches are useful for letting users update their preferences and settings, and should be intuitive to use.

There are several different ways to manage toggle configuration, ranging from relatively simple but static approaches through to highly sophisticated systems which can support dynamic in-memory re-configuration of feature flags and their associated configuration. In most cases it is preferable to manage toggle configuration via static files, but there are some situations where this approach cannot be applied.

If a toggle requires runtime configuration it is wise to consider using an endpoint to enable dynamic in-memory re-configuration. This will avoid requiring a team to restart their process or re-deploy their artifacts in order to flip a toggle.