Feature Flags with PostHog

Quick Guide: Use PostHog feature flags for gradual rollouts, A/B testing, and remote configuration. Client-side: useFeatureFlagEnabled hook. Server-side: posthog-node with local evaluation. Always pair useFeatureFlagPayload with useFeatureFlagEnabled for experiments. Handle the undefined loading state on every flag check.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST always pair useFeatureFlagPayload with useFeatureFlagEnabled or useFeatureFlagVariantKey for experiments - payload hooks don't send exposure events)

(You MUST use the feature flags secure API key (phs_*) for server-side local evaluation - personal API keys are deprecated for this use)

(You MUST handle the undefined state when flags are loading - never assume a flag is immediately available)

(You MUST include flag owner and expiry date in flag metadata - flags without owners become orphaned debt)