Feature Flag
Feature flags decouple feature release from code deployment, toggling functionality at runtime to enable progressive delivery and instant rollback.
Purpose
Control feature visibility at runtime, reducing release risk.
Mechanism
Code switches behavior with if flag. Flag services (LaunchDarkly/Unleash) manage flag state. Progressive rollout (percentages/user segments). A/B testing. On failure, flip the flag off—no redeploy needed.
Use cases
- Progressive delivery
- A/B testing
- Instant rollback