Deployment Technique: Feature Flagging

• Feature flags are a software development technique that allows one to turn a feature on or off without modifying the source code or requiring a redeploy.
• Feature flags are used to control this traffic switching. The developer could use a feature flag to turn off the new feature for all users or a subset of users while you are testing it. Once satisfied with the new feature, you can enable the feature flag and start serving it to all users.
• They are also commonly referred to as release toggles, feature toggles or feature flippers.
• Feature flags are used in blue-green and A/B testing deployments to control which version of the application is served to users.
• For example, you could use a feature flag to test a new pricing plan with 10% of your users. If the results of the A/B test are positive, you can then deploy the new pricing plan to all users.