A toggle is a switch or button that allows users to select between different states or options. Toggles are used in a variety of settings, including technology, computing, programming and communication. Toggles are a common tool in software development to support Agile practices, as they allow teams to deliver features that are still under construction without creating code branches and having to go through a lengthy testing and QA process.
Using feature flags allows teams to experiment with features and changes in a controlled way, then roll them out in small increments to a percentage of users in order to gather data and collect feedback before rolling the change out to all users. This is a powerful technique for continuous deployment and it is used extensively at Facebook, Etsy and many other companies.
Toggles can be implemented in a number of ways and they are often hidden within application logic or within other features that are activated when certain conditions are met. Typically, they are set up as boolean variables that have a value of 1 or 0. Once a toggle is flipped on it will enable or disable the underlying functionality. A toggle can be triggered by any event such as a click or a change in user data that triggers the corresponding action.
Most toggle configuration is stored in static files and this can become cumbersome for large applications. For this reason, many organizations move their toggle configuration to some type of centralized store, often an existing application DB. This is accompanied by the build-out of some form of admin UI that enables product managers, testers and system operators to view and manage the toggle configuration.
One of the biggest challenges with using toggles is keeping track of their lifecycle and ensuring that they are removed from the codebase once they have been proven or not necessary. Savvy teams recognize that a feature flag comes with a carrying cost and try to keep the inventory of toggles as low as possible. They do this by adding a toggle removal task to their backlog when they first add a Release Toggle and by setting “expiration dates” on their toggles so that a test will fail (or even refuse to start an application!) if the toggle has not been removed from the codebase before the expiration date.
It is also important to ensure that toggles are not result macau lingering in production too long, as they can drive up database traffic as users query the toggle state and rely on other visual clues (colors in particular) to determine the toggle’s state. In general, it’s best to use a UI pattern that does not rely on colors to convey meaning as those cues can be inaccessible for many users, especially those with red/green color blindness. If you need to use a toggle in the front end, try to use a header or query parameter so that it does not require a database call.