The word toggle comes from the 18th century definition of “pin passed through the eye of a rope to fasten.” In web development, it’s an important user interface element that lets you change settings or other attributes. But implementing toggles correctly can be challenging. For example, you need to use direct labels and make sure your toggles have a clear, visible state. If you don’t do these things, your toggles could be confusing and difficult to use. Toggle switches also need to be accessible for visitors with disabilities. So you need to provide them with a clear label, make the toggle switch look like a slider and use visual cues that indicate its current state.
The most common use for a toggle is to quickly switch between two states. For example, if you want users to be able to enable or disable an airplane mode feature, you’ll create a toggle for the setting. If you want to give users the option of changing their default email program from Gmail to Microsoft Outlook, you’ll build a toggle for that too.
Using toggles allows you to add features in the middle of your normal software development process. Traditionally, you’d write new features on code branches and go through a lengthy testing and QA process before you can integrate them into the main branch. But you can hide these features behind toggles, so they’re not available until they’re ready to go public. This is similar to what is often called a canary release or a feature flag.
When using toggles, you should keep them to a minimum and always consider the impact of each one. For example, if your toggle is a setting that affects the entire application and you use it in production, it will increase traffic because every time you change a value for that toggle, all the users will have to get that information from a database. That can be thousands or millions of database queries for a single value that may only be changed rarely.
Another thing to think about is how the toggle will affect your database’s read performance. If you have a large number of toggles in your database, you’ll be doing thousands or millions of read queries for each of the toggles. This can negatively impact your application’s performance, especially in production. To avoid this, clean up your toggles frequently and never have more than a few in your database at any given time.
Another consideration when using toggles is whether they’re the best UI for the feature you’re trying to implement. If you’re adding a setting that isn’t binary or doesn’t require instant action, it might be better to use a different UI component like a checkbox in combination with a button. And if you’re fixing a bug, it’s worth considering case by case whether toggling the behavior around the bug is needed. That way you can ensure that your fix doesn’t accidentally worsen the problem.
