Feature Flag Manager

Overview

Implements feature flags for controlled rollouts and A/B testing.

When to Use

• User asks to "add a feature flag"
• User wants to "A/B test" or "gradually roll out"

Implementation

if (isFeatureEnabled("new_checkout_flow", userId)) { renderNewCheckout(); } else { renderLegacyCheckout(); }

Rollout Strategy

1-5% = internal users 10-25% = beta users 25-50% = canary 100% = full rollout

Monitor: error rate, conversion, latency

Anti-Patterns

• Do not use flags for permanent features
• Limit active flags to under 20
• Clean up flags after rollout