A toggle is a button or switch that can be pressed to turn on or off something. It’s a simple user-interface component that can have a big impact on user experience and usability. When used well, toggles can help users update preferences and settings or enable new features without requiring them to re-enter their password or login information.

A common practice is to use toggles for features that aren’t ready for prime time but you want to make available to a subset of your audience or user base. This allows you to test and optimize those features without risking the whole population. In general, it’s best to limit the number of toggles a product has to avoid overwhelming the user experience.

Toggles are a key tool for running multivariate or A/B tests. By having a toggle configured for a given cohort of users you can consistently send that cohort down one codepath or another at runtime. This is commonly done to experiment with things like the Call To Action wording on a button or the purchase flow of an ecommerce system.

When using toggles be sure to provide clear labels for the current state of the switch. Also be sure to use standard visual design conventions. Finally, be aware that toggles can create accessibility issues for screen reader and assistive technology users. The color contrast between a toggle switch’s on/off states can be difficult for these users to perceive. It’s important to have good accessibility testing to be sure that your toggle switches are accessible to all users.