A toggle is a switch that has two positions: on or off. They’re commonly used in technology and programming to provide users with the ability to switch back and forth between settings or modes.
In software development, toggles are useful for enabling or disabling code paths that aren’t ready to be released. For example, if your team is implementing a new algorithm that will be resource-intensive or requires additional testing or user data to be fully developed, you can create a toggle that hides that code so that it’s not exposed to your entire user base until your team is confident in its performance and quality. This allows your team to release a product while still working on the feature without holding up the rest of the product’s releases.
Toggles can also be useful for adjusting the default state of system functionalities like airplane mode. They’re the preferred control for adjusting settings on mobile because they offer more precise options (either ON or OFF) and take up less screen real estate than a radio button pair. Unfortunately, many web designers and developers fail to consider accessibility when using toggles. For instance, they often use the color green to represent ON and red to represent OFF which doesn’t work for many users who have color blindness (8% males).
There are several ways to implement toggles in your software. Some approaches are more dynamic than others and allow you to re-configure the toggle’s state as needed. This includes commenting on the code to define a new state and using a preprocessor’s #ifdef feature, where available. These approaches have some downsides however, especially if you’re making frequent changes to your toggles or are releasing many small updates.
Another approach to implementing toggles is to use a separate class that can handle the logic for managing and configuring your toggles. This is generally more robust than the commenting or preprocessor approach, but it can add complexity to your software.
Feature toggles are also a common tool for deploying A/B tests and other experiments in production software. When a toggle is enabled for a cohort of users, the toggle router will consistently send that user down one codepath or the other to measure the impact on their behavior. This type of testing is more efficient than having to make the same change to every user at once and can be very effective in making data-driven optimizations.
