A toggle is a switch used to change the state of an object (such as a light bulb or a computer display). The word toggle derives from the action of turning something on and off.
Toggles are widely used in everyday technology devices and applications, for example in hardware devices to control the power or in software applications to enable or disable functionality. They can be found on phones, tablets, laptops and desktop computers to adjust various settings such as the keyboard brightness or screen resolution.
In software development, toggles are a useful tool for debugging and prototyping complex features. Typically, they allow developers to disable an entire feature so that they can work on a specific part of the system without impacting other users. In this way, toggles can provide a safe environment for experimentation and rapid iteration that is difficult to achieve in a production environment.
Many teams use a toggle in their development process as a quick and easy way to enable or disable new features. Unlike feature branches that require a complete codebase to build out, these toggles can be turned on and off at runtime – providing a flexible configuration mechanism for a product. Unlike a traditional checkbox or radio button, which rely solely on color to convey meaning, toggles can be configured with any number of states based on an array of different conditions. These can include fitness test results from other features in the codebase, a set of criteria defined in a feature management system or even a simple input variable passed to the toggle from a config file.
The use of toggles in development is a common practice for agile software projects as it reduces the amount of manual rework required for a team to get to their next release point. However, there are some important considerations that should be taken into account when implementing toggles for use in a production environment.
One of the most important aspects of toggles when used in production is that they must be designed with accessibility in mind. This includes using high-contrast colors to make them easier for users to interpret. Additionally, designers should consider WCAG guidance and the cultural or societal implications of the toggle’s default on/off states. For instance, using red as the default for on and green for off may not be a good choice for some user populations who associate these colors with stop signs or traffic lights.
Savvy teams view the Feature Toggles in their codebase as inventory that comes with a carrying cost and seek to keep this inventory low. To accomplish this, they are proactive in removing toggles that have been deprecated or no longer needed. Some teams even create expiration dates on their toggles to ensure that they are removed by a given date if possible. This prevents them from being accidentally reintroduced into a product, which could negatively affect the customer experience or create additional technical debt.
