Progressive Delivery: Scenario-Based Questions

Feature flags are toggles that allow dynamic control over feature exposure without redeploying code. They’re core to progressive delivery strategies like canary releases, A/B testing, and staged rollouts.

🚦 Benefits of Feature Flags

• Decouple deploy from release — ship code without turning it on for everyone.
• Test in production safely with canary cohorts or internal users.
• Enable instant rollback by disabling flags if issues occur.
• Personalize user experiences with targeted flag rules.

📊 Common Use Cases

• Beta features for select users or regions.
• Gradual rollout of backend refactors or UI redesigns.
• Operational toggles (e.g., disable payment provider if it’s down).
• Experimentation and conversion tracking (A/B tests).

🧰 Flag Management Tools

• LaunchDarkly, Flagsmith, Split.io: Full-featured SaaS with SDKs and dashboards.
• Unleash, Flipt, OpenFeature: Open-source and pluggable systems.
• Custom flags: Config maps, environment variables, or DB-driven toggles.

✅ Best Practices

• Expire unused flags — use TTLs or flag cleanup policies.
• Separate flags by category: release, experiment, ops.
• Use type-safe flags with default fallbacks.
• Log flag states with telemetry for debugging.
• Secure flag evaluation (no logic in the frontend that reveals gated features).

🚫 Common Pitfalls

• Leaving stale flags that clutter code and logic.
• Hardcoding evaluation rules into app logic instead of using a provider SDK.
• Over-using flags for configuration rather than release control.

📌 Final Insight

Feature flags are a force multiplier for velocity and safety. They turn release risk into something testable and reversible — helping teams iterate faster with fewer outages or regrets.