A toggle is a kind of switch which allows users to choose between two different states. In software development, toggles can be used to enable/disable features. They are particularly well suited for settings, preferences and other kinds of information that users have to update frequently. Toggles help to make these updates quicker and easier. For this reason, they are usually preferred over checkboxes.
In addition to their speed of use, toggles are also known for being simple and clear for users. This is especially important on mobile where screen real estate is limited. Good toggle switches should be clear about what they will do if switched to ON and what their current state is. It’s helpful to think of them as sliders and to use visual cues such as movement and color to avoid confusion.
It’s a good idea to test toggle configurations before they go live in production. This can be done by testing a scenario with the toggles flipped on and then again with the toggles flipped off. This will allow you to verify that existing or legacy behavior is enabled when a feature is flipped on and disabling it when it’s flipped off.
Typically, it’s a good idea to limit the number of toggles you have in your product. This will help keep the complexity of your code down and make it easier to maintain. It’s also important to have a system for managing and configuring these toggles. This can be a manual process or it could involve some type of centralized store, depending on your architecture.
In many cases, a simple toggle file in your source control system will suffice. However, as your product grows it may be necessary to move to more sophisticated methods for managing toggle configuration. For example, comments and preprocessor features are sometimes used to hardcode toggles into a piece of code. While this approach doesn’t offer dynamic re-configuration it can be a good fit for short-lived release toggles.
On the other hand, a more sophisticated toggle management system will often require the implementation of a centralized store and some form of admin UI which product managers, testers and systems operators can access. This will allow the toggle to be re-configured at runtime and can reduce the need to re-deploy an artifact for tests to take effect. Some teams even put expiration dates on their toggles to make sure they get removed from the backlog when they’re no longer needed.