Toggle is a user interface component that lets users change preferences, settings, or other types of information quickly and easily. When implemented well, toggles provide a consistent and familiar user experience across platforms. This is why it’s important to use them sparingly, but strategically – implementing toggles in the right place can make a big difference to your users. When you do, be sure to provide direct labels, use standard visual design, and deliver immediate results.
The word “toggle” comes from the action of physically switching a piece of equipment on or off, like a light switch or a car’s dashboard lights. In software, toggles have a similar purpose – they allow you to test changes in your product with only a small percentage of your users and then remotely rollback those changes if needed. This is known as an A/B test.
Feature toggles are extremely useful when it comes to development because they help teams quickly deploy, test and maintain features while minimizing code deployments. But they can also create a lot of complexity and friction in your production environment. To prevent this, savvy teams treat their Feature Toggle inventory as a resource that comes with a carrying cost and seek to keep it low. To do this they are proactive about removing Release Toggles when they are no longer needed and some even put expiration dates on them (which will fail tests or cause your application to crash if a toggle is not removed by the time of the expired date).
While using Feature Toggles in your codebase, you should always be mindful of how your users will perceive it. For example, the choice of color to indicate state change is important and should be evaluated based on accessibility (for example, it’s not helpful to use red as it carries negative connotations for some users). It’s also important to avoid ambiguity by providing descriptive labels and using a clear visual cue to show the toggle’s current status.
When a toggle is flipped On, your users will see new behavior in the browser while the old, existing behavior remains hidden. Ideally, it should be easy for them to revert the toggle back to Off. To do this, you can either use the toggle’s default state or a fallback value that the toggle will automatically revert to when it is flipped Off.
Many teams also perform a full regression test for every release against a full set of toggle configurations including the release’s Release Toggle flipped On and the fallback toggle configuration that it will revert to if the Release Toggle is flipped Off. This ensures that the release will behave as expected and reduces the risk of a bug being introduced in the future. This is especially valuable for teams that follow a trunk-based approach to development and have a fixed branch in their source code management tool.
