A toggle is a switch that provides a user with the option to change between two states or options. Toggle switches are commonly used in technology, computing and programming to allow users to switch between different settings or modes. For example, on a smartphone you can toggle between screen resolutions and audio quality, or the ability to use the camera in landscape or portrait mode.
In software development, toggles are used to manage the release of new features and functionality. By using a feature flag system, developers can create toggles to allow teams to incrementally roll out changes into production while maintaining a stable master codebase. This approach reduces the impact of bugs and improves the speed at which feedback can be delivered to the development team.
Toggles can be created for a number of purposes, and there are some best practices for how they should be used. One of the most common uses is to enable a dev team to work on a new feature without impacting existing production functionality. This can be a great way to get a prototype into the hands of users quickly, and it also allows the business to track user behavior and learn from their experience with the new feature before it is ready for broader rollout.
Another popular use for toggles is to perform multivariate or A/B testing. By encapsulating the implementation of the test into a toggle, it is easy for development teams to run controlled experiments to understand which configurations are performing better. This is an important technique to have in your toolkit, and it can lead to a lot of insights about your customer base that would be difficult to determine otherwise.
While there are good reasons to use toggles in most situations, there are some circumstances when they can be confusing. First and foremost, it is essential that you use clear, concise labels for your toggles. They should describe what the control will do when pressed, and they should be consistent in their wording across your application. This will make it easier for the end user to understand what is happening, and will also reduce cognitive load.
Color is an important visual signifier for toggles, but it is a mistake to rely solely on it. Using high-contrast colors (and providing state descriptors) can help to eliminate confusion, but you should also consider cultural and societal implications when choosing your toggle color. For example, some users may have red/green color blindness and might find a toggle that uses green as its on position very difficult to comprehend.
It is also important to ensure that you can exercise all the possible toggle configurations in your QA environment. Often this requires modifying static files, or at the very least, restarting your QA server to apply the change. In order to streamline this process and maintain the rapid feedback cycle that CI/CD makes possible, many teams will deploy their toggle configurations into a centralized config DB, which will then be accessible in-memory during tests.
