feature-flag-system

# Feature Flag System Skill Implement feature flags to toggle features, run A/B tests, and control rollouts without redeployment. ## Purpose Enable gradual feature rollouts, A/B testing, kill switches, and environment-specific behavior. ## When to Use - Gradual feature rollouts (10% → 50% → 100%) - A/B testing different versions - Beta features for select users - Kill switches for problematic features - Environment-specific features ## Quick Start ```bash python3 /home/ubuntu/skills/feature-flag-system/scripts/setup_flags.py /path/to/project ``` ## Usage Example ```typescript import { useFeatureFlag } from '@/lib/flags' export function Dashboard() { const { enabled } = useFeatureFlag('new_dashboard') if (enabled) return <NewDashboard /> return <OldDashboard /> } ``` ## Common Patterns ### Percentage Rollout ```typescript // Roll out to 25% of users const rollout = 25 const userHash = hashUserId(user.id) % 100 if (userHash < rollout) { // Show new feature } ``` ### User-Based Access ```typescript const betaUsers = ['user1', 'user2'] if (betaUsers.includes(user.id)) { // Show beta feature } ``` ## Providers - **Vercel Flags** - Built-in, free - **PostHog** - Open source, analytics included - **LaunchDarkly** - Enterprise-grade - **Split.io** - A/B testing focused ## Time Savings **Manual**: 1-2 hours **With Skill**: 10-15 minutes **Saved**: ~1.5 hours per project ## Files - `scripts/setup_flags.py` - Automated setup - `templates/feature-flag.tsx` - React hook - `references/flags_patterns.md` - Best practices ## Related Skills - `analytics-dashboard` - Track flag usage - `deployment-automation` - Deploy with flags - `testing-framework` - Test flag variations *Ship features safely with instant rollback capability.*