A toggle (or feature flag) is a piece of user interface code that allows developers to alter the behavior of their software at runtime. Toggles allow teams to test out new features before integrating them into production, enabling companies to gather real-time customer feedback, speed up release cycles and pave the way for continuous improvement. However, implementing and managing toggles presents a set of unique challenges. Here are some tips for overcoming these complexities to leverage the full benefits of this powerful tool.

Toggles are often used in conjunction with form elements like checkboxes and radio buttons to update user preferences, settings and other types of information. Because toggles can be difficult to interpret, it’s important to provide clear visual cues, particularly when a toggle has multiple states. This can be achieved by ensuring the toggles are recognizable as buttons, using standard visual design and updating their appearance based on their state.

It’s also a good idea to limit the number of toggles that are active in your software at any given time, and to remove them as soon as they are no longer necessary. This will reduce the number of complex conditional statements in your codebase and help maintain code readability. Additionally, make sure you have a process in place to regularly prune the number of idle toggles that exist in your codebase.

Another common use case for toggles is in experimentation and A/B testing. By allowing you to assign different sets of users to different experimental paths, toggles can be used to determine which feature performs best and provides the most value for your customers. Experimentation toggles can be a great way to reduce risk when launching new features, and they also offer a more controlled environment than a code branch in more traditional waterfall development processes.

Finally, it’s important to avoid overusing feature toggles, as they can have a negative impact on performance. For example, if you’re using toggles to create dynamic settings, each change in the state of a toggle will trigger a database call. If you have thousands of toggles causing these queries, it could cause a noticeable performance hit in production even before the feature is released.

The Name Matters

When creating feature toggles, it’s important to give them descriptive names that are easy to understand. This will help you avoid misinterpreting the purpose of a toggle and can help you keep track of which toggles are enabled and which ones are not. To further enhance clarity, it’s a good idea to use color to identify a toggle’s state. This can be helpful to users with visual impairments who might rely on color as a primary cue.

It’s also worth considering whether a toggle should be created around bugged behaviour, as this may add complexity to the fix and increase the likelihood that the fix will actually worsen the original problem. It’s best to decide on a case-by-case basis whether a toggle is needed for a ticket and to create it only when there is a clear benefit for doing so.