A feature toggle (also known as a feature flag) is a software development technique that allows developers to enable or disable features in a system without deploying new code. This mechanism provides a way to control the activation of new features at runtime, giving teams the flexibility to test and release code incrementally, reduce the risk of introducing bugs in production, and enable continuous delivery practices.

Feature toggles can be used to implement A/B testing, canary releases, or even to turn off a feature in the case of unforeseen issues in production. Toggling allows non-disruptive deployment, as teams can release code with features hidden behind toggles and activate them later once they’re fully tested and ready.

Feature toggles are especially useful in agile development and DevOps environments, helping to increase the pace of deployment while maintaining control over feature exposure and stability.