A toggle is a switch that has two states, either on or off. In technology applications, we often use toggles to enable and disable features. We also use them to switch between settings or display modes. For example, we may toggle between the stream and map views in a streaming video or we might toggle between the zoomed-out and enlarged view in a photo editing program. Toggles are found in everyday technology devices, including smartphones and tablets, as well as software applications like chat apps, photo editors, streaming video programs, and social media platforms.
Toggle switches should be labeled clearly, preferably using a consistent visual design. The wording should be direct and easy to understand, as users will likely only be able to change the state by pressing the toggle. For the sake of accessibility, toggles should also not rely solely on color for meaning. Checkboxes and radio buttons work better in this regard, as they are less likely to depend on color alone to convey their current state.
In general, a toggle should not be used to implement features that require a long and rigorous testing and debugging process. A release toggle, for example, should be removed from production code as soon as its purpose is complete. If a feature toggle remains in place for too long, it can interfere with the stability of other features and even the product as a whole.
One of the best ways to avoid this is to limit the scope of a feature toggle and to ensure that it does not overlap with other features. For instance, a nav bar or sidebar might be configured as a toggle, but it should not be used to control other features such as the search or login options. Similarly, a toggle for an e-commerce site’s recommendation algorithm should not be used to provide different types of navigational experiences.
Many teams use some type of centralized database or config file to manage feature flags, which makes it easier for developers and testers to update the state of a toggle with a single change. The centralized system can also help track changes to a toggle across releases and deliver stability benefits.
Some teams choose to hardcode the toggle configuration within their codebases via a simple if statement or preprocessor flag (e.g., #ifdef). This approach can be cumbersome and error-prone once a project scales to multiple servers or deployments. A more sophisticated solution is to manage feature flags using some type of centralized database or config store, which offers the benefits of dynamic re-configuration and ease of management at the cost of some additional complexity. Regardless of which approach is taken to managing feature flags, it is essential that the configuration is managed in source control so that any team can quickly understand the intended state of a toggle. In addition, this also allows the team to quickly revert back to a previous release.
