A toggle is a small piece of material used to fasten or adjust something. Toggles are used in technology, computing, programming and communication to enable users to manage the state of a system. A common use is to toggle between different settings or modes.
Feature Toggles allow development teams to change the behavior of their applications in a controlled way without changing core code. This allows them to test and evaluate changes in a small percentage of their user base before rolling them out to all users. This helps mitigate the risk of new regressions being released in production, and it can improve user experience.
When used as a UI element, toggles are most effective when they help users manage the state of content or views. They should always be clear about their purpose, provide direct labels, and use standard visual design principles. For example, using the color red to indicate a toggle’s on position can be counterintuitive for some users who associate this colour with stop signs and traffic lights. It’s also important to consider cultural differences when selecting a toggle’s on/off states.
In addition to testing the toggle configuration that is expected to go live in production, savvy teams regularly schedule tasks for removing toggles that have been active for a while. Some teams even put “expiration dates” on their toggles, ensuring that they are removed before they become out of date.
While there are a variety of ways to implement toggles, many choose to store them in a centralized repository to maintain control and visibility. In this way, developers can easily locate a toggle’s configuration and understand its purpose in the context of an application. Other developers might choose to hardcode a toggle’s configuration in their codebase, either by commenting or using a preprocessor feature like #ifdef. This approach is less dynamic and doesn’t allow the re-configuration of a toggle after it has been deployed, so it is only suitable for toggles that aren’t expected to be re-configured frequently.
Adding toggles to your development process supports agile approaches and enables you to release features before they are fully ready. For example, you could use a toggle to experiment with different suggestion algorithms in an A/B test. Once the results of the experiment are conclusive, you can switch the toggle to the winning algorithm and roll it out for all users. This is much faster than developing and testing a new feature on a separate code branch before integrating it back into trunk code, which would be necessary under traditional waterfall development models. However, it’s crucial to develop a consistent process for managing your toggles to avoid creating technical debt. This includes implementing a consistent naming convention and using tools that can assist with flag management, such as LaunchDarkly. This will ensure that your toggles are named in a consistent manner across all releases and that they are always clearly understood by other developers.
