Feature flags separate deployment from activation and support gradual rollout, experiments, tenant targeting, and emergency disablement. A flag platform needs stable evaluation rules, audit history, ownership, caching, and behavior when configuration is unavailable.

Flags create hidden complexity when stale branches remain forever or many flags interact. Assign owners and cleanup dates. Authorization must not depend solely on a client-side flag because clients can bypass UI controls.

Configuration propagation is a distributed state problem: instances may receive a new value at different times. Use versioned configuration, validation before publication, staged rollout, and rollback. Define whether stale configuration is acceptable for critical controls and how clients detect invalid snapshots.