Feature Flags and Progressive Delivery Questions

Design and operation of feature flagging and progressive delivery systems. Candidates should be able to explain patterns for decoupling deployment from release, types of feature toggles such as release toggles, operational toggles, experiment toggles, and permission toggles, and strategies for flag evaluation and storage. Cover rollout strategies including canary deployments, blue green deployments, ring based rollouts, dark launches, and user segmentation with safe rollback procedures. Discuss integration with continuous integration and continuous delivery pipelines, automated gating based on metrics, feature flag governance and lifecycle management including flag cleanup, testing strategies for toggles in pipelines, performance and security considerations, and how to instrument and observe the impact of toggles to support metric driven releases.