A toggle is a switch that allows you to change between two different states or options. Typically toggles are used in technology, computing, programming and communications to allow users to modify settings or modes quickly and easily. A toggle can be pressed or clicked to activate the active state and then deactivated when no longer needed. It is common to use toggles as part of responsive design and web development to enable different layouts or displays depending on the device or screen size.
Feature Toggles are a very useful tool for software development teams to support a wide range of test and experiment scenarios. They enable developers to re-configure code at runtime by switching between a variety of codepaths for individual users. This can be incredibly powerful and allows for very fast data-driven optimizations to be made to things like the purchase flow of an ecommerce system or Call To Action wording on a button.
The key to using toggles effectively is that they should be limited in scope and used sparingly. It is tempting to use toggles to enable large swaths of functionality but this is often confusing for users and can lead to unintended behavior which can be very difficult to fix weeks or months down the road when it begins impacting other features.
Another best practice with toggles is to clearly label them with a meaningful name. This provides helpful context when reviewing error messages from the system and ensures that everyone understands what each toggle does. It’s also a good idea to use visual cues for toggle switches such as a slider or switch so that users can immediately identify the current state.
A final best practice with toggles is to only use them for specific tests and experiments. This limits the amount of configuration that is exposed to a single user and helps to ensure consistency in test and production environments. It’s also a good idea for teams to test their toggle configurations in the same way that they will be deployed to production to avoid any surprises.
Finally, many teams choose to move their toggle configuration from static files to a centralized store (often an existing application DB) to make it easier for product managers and system operators to manage and modify them. This usually also enables teams to create a more robust admin UI for viewing and modifying feature flags. Some organizations even put “expiration dates” on their toggles to ensure they are removed from production at a certain time. This prevents them from accidentally being re-introduced in future versions of the software.