A toggle is a switch between two states or options, often used in software to provide control over features or settings. They are common in responsive web design to adjust layouts and displays based on screen size and device. They can also be found in content elements like collapsible sidebars and accordions.
In software, toggles are implemented as boolean variables that can be flipped between two states, on or off. Usually, when the toggle is flipped on, it activates the feature or changes the setting that it was previously disabled.
Toggles are a great way to support dev teams as they write new code. Instead of creating a new branch where they’re writing the feature, they can generate a release toggle in their master codebase that will leave it inactive while they work on it, and still allow them to push updates to production to meet delivery targets.
This makes the toggle easy to reset and allows devs to experiment with a feature without impacting other teams working on different features or exposing users to potential bugs. It’s important to avoid toggling large swaths of the codebase however, because it can introduce cognitive issues for developers who need to remember which toggles are flipped on and which are flipped off.
Toggle configuration can be as simple as a comment or as complex as a decision tree and can be used to control a wide variety of behavior. A wide variety of conditions, from fitness test results in other parts of the codebase to settings in feature management software, can determine which way a toggle flips. This flexibility can be a positive attribute of toggles, but it can also make them prone to errors and maintenance challenges.
Another important consideration when using toggles is that they should be easily accessible to all users. Unfortunately, this isn’t always the case. Many designers use green and red as labels for on and off, but these colors can be confusing to users who have color blindness or low vision. Additionally, many users of assistive technologies may not be able to reach the toggle element itself.
In general, it’s important to test all of the toggle configurations that are expected to go live in production. This includes testing the current toggle configuration plus any that you intend to release flipped On, as well as the fallback toggle configuration that will enable old or legacy behavior if the new toggle is flipped Off. It’s also a good idea to perform some tests with all toggles flipped Off, since this can help prevent regressions from sneaking into production that would be impossible to fix months down the road.
It’s also worth noting that while toggles can be a great tool for managing change, they can negatively affect performance if there are too many of them in production. This is especially true for dynamic toggles that are stored in databases. When this happens, we’re generating thousands or even millions of database calls just to read one toggle configuration, and it can quickly become overwhelming and expensive.
