How to Define a Toggle

A toggle is an up-and-down switch used in both hardware and software. Toggle switches can be found in many settings menus and options boxes, allowing users to change a specific function’s status.

When defining a toggle, it is important to think about what the control will do when the user switches on or off the switch. This is essential to avoid confusing the user and causing them to click on or off the control incorrectly.

In addition, a good toggle should provide clear labels that describe the functionality of the control. This is especially true for toggles that require a user to choose between two opposing states.

Labels should be direct and concise, limiting the total number of words to a minimum. The best labels use one or two words, preferably nouns that describe the functionality of the toggle control, and should be simple to understand without requiring the user to read an entire paragraph.

Visual design and state loop animation

Whenever possible, make sure that the toggle switches look like sliders with visual cues to indicate which direction the control is moving in. This will help avoid confusion and reduce clicks on the control, which can negatively impact conversion rates.

Keep the number of toggles as small as possible

As you grow your Feature Flag inventory you will need to be more proactive in removing toggles that are no longer needed, reducing the amount of toggle clutter in your codebase and making your release cycle more predictable. Often, this is accomplished by placing an “expiration date” on toggles that are not being re-used as part of new releases and implementing a process to remove them before the end of their life.

Configuration of Feature Toggles

As a rule of thumb it’s better to manage feature toggle configuration in static files rather than in a centralized store. Modifying toggle configuration files can be a fiddly operation, particularly when you are managing a large deployment fleet and need to ensure consistency across all servers.

Some teams use a commenting mechanism to allow them to modify toggle configuration at runtime. This allows them to override the default configuration of a feature flag and perform dynamic re-configuration in response to changes in the system, or in response to a request from a tester.

However, this approach does come with a lot of complexity. For example, a team may need to deploy the configuration of a toggle every time they want to flip it from Off to On, a process which can take significant time to execute. This can have a negative effect on the cycle time of the validation process which can in turn affect CI/CD.