Toggle is a term used to describe an on/off switch that can be flipped. In everyday technology, toggles can be found on devices like mobile phones that enable and disable WiFi, or computers that allow you to turn on and off the caps lock key. In programming, toggles are used to control features such as notifications, display modes and other user-defined settings.
In software applications, toggles are a useful tool for developers to quickly test and deploy new features without impacting existing functionality. Toggles can be hidden from users with a simple click and then enabled once the team has finalized the feature. This enables rapid iteration and allows developers to get feedback from real-world users.
Toggles are an essential tool for any modern development process. By adding a layer of flexibility and security, they allow teams to deliver features faster while still being safe from production regressions. Toggles also help to support newer agile processes, such as code sprints and continuous delivery. By using them, teams can get features into production even while they are still in progress, rather than requiring them to be developed on branches under more traditional waterfall development models.
However, like any tool, toggles are not infallible and should be used with caution. It is important that you take care when implementing toggles to ensure they are designed in a way that will be accessible to all users, including those with accessibility needs. Many web designers use toggles that rely on color to communicate states, but this can be difficult for users with visual impairments. The good news is that there are ways to make toggles more accessible — check out our Accessibility article for tips on how to do so!
Another potential downside of toggles is that they can be quite performance-intensive. If a toggle is dynamic and stored in a database, it can trigger a database call each time it is flipped. This can add up over time, especially if the toggle is frequently re-flagged. To help alleviate this, many teams move their toggle configuration from static files into some form of centralized storage, usually an existing application DB. This often accompanies the build-out of some kind of admin UI for users to manage their toggle configuration.
In addition to a performance benefit, having all of your toggles in one place makes it easier for teams to collaborate on them. By having them all in source control, it is much easier to manage versioning and to ensure that each feature can be rolled back if necessary. By following best practices such as defining toggle ownership, automating documentation and auditing your toggles on a regular basis, you can maximize the benefits of these powerful tools while also keeping them under control. For more information on best practices for managing feature flags, we recommend reading Martin Fowler’s article or exploring the resources at Statsig.
