A toggle is a control that lets people choose between opposing states like on and off. Toggles use a different appearance to indicate each state, and they are commonly used in technology, computing, programming, and communication.

A Toggle can be anything that changes from one state to another, such as a light switch turning on a lamp. However, they are most often used in software as a means of running experimentation and A/B testing. They can also be used to change the behavior of an existing feature without changing its code base. This makes it easier to validate new features before they go live.

Toggles are very useful and powerful tools, but they can cause a lot of problems when not managed well. To prevent them from slowing down your CI/CD process or creating bugs when they are not in use it is important to limit the scope of each toggle as much as possible and to keep them under a minimum of control. For example, if you have an experiment toggle that re-configures the behaviour of an entire service instance this can cause a lot of extra database calls and slow down your validation cycle. To avoid this it is good practice to expose a runtime configuration endpoint and allow for dynamic in-memory re-configuration of the toggles you want to test with.

Another consideration is that it can be hard for users to understand the current state of a toggle. This is especially true if the toggle uses color to convey its state, which can be problematic for accessibility reasons. To avoid confusion, it’s best to use a non-color signal to denote state and consider using label text that clearly states the toggle’s current state.

Finally, it’s essential to be proactive in cleaning up your toggle inventory so that you don’t have a lot of unneeded toggles taking up memory and slowing down your system. Savvy teams view their feature flags as inventory that comes with a carrying cost and try to reduce the number of toggles in production as much as they can. For example, they might add a task to the backlog to remove a toggle as soon as it has been implemented. Some teams even put “expiration dates” on their toggles to make sure they are removed before they can negatively impact a release.

This article is available to Grandmaster subscription tiers and above. Please log in to continue reading.

Have a question about Evolve? We’re here to help!

This is a place where you can ask anything, from basic questions as you get started with the platform to complex best practice issues. Our team of experts will be happy to assist you.

Have you found this article helpful? Help us improve it by sharing your feedback with our team. Thank you for your interest in Evolve!

The ability to quickly re-configure specific feature instances during a development cycle is incredibly valuable. However, it is easy to over-use the feature toggle and end up with a sluggish or confusing product.