A toggle is a switch that has two states, on and off. It’s a simple concept, and it’s used in all kinds of ways. For example, you might use a toggle to flip between screens as you video chat with two people at once. Or, you might use a toggle to change your default browser to another program. And, of course, in software, you can toggle features on and off using release toggles.
In development, toggles let engineering teams test new code in a production environment without risking the experience of all users. They can also remotely roll back these toggles after testing is complete, enabling them to practice blue-green deployment.
Generally, release toggles are short lived, and should only be active during the time your team needs to develop and test a feature. Having too many toggles in your codebase can be confusing for other developers and make it difficult to debug if something goes wrong. It’s best to have a small number of toggles that are active at any given time.
If you have more than one toggle active at the same time, it’s important to clearly communicate what each toggle is doing and why. This helps everyone understand the impact of the toggles, and minimizes confusion about which toggle is controlling the feature. It’s also important to keep a toggle’s scope limited, so it doesn’t affect too much of your product at any given time. If a toggle controls multiple features or parts of your application, it’s a good idea to create counter toggles that remove the feature when you need to deactivate the toggle.
Toggle types help you categorize the different toggles in your codebase. You can then manage each toggle type differently. For example, you might label a toggle “Cookies” or “No cookies.” In this way, you can see at a glance what each toggle does, how long it’s been in your codebase, and how many users it affects.
A toggle can be anything from a single statement of condition to a complex decision tree, based on many different conditions. These conditions can be fitness test results from other features, settings in your feature management software, or a value provided by a config file. During runtime, your system reads the configuration of the toggle and, if ON, executes its function. If OFF, your system ignores the toggle. You can also change the configuration of a toggle at runtime, without changing any source code, by querying an outside data source like Kameleoon. This is especially useful for enabling trunk-based development and performing multivariate or A/B testing.
