posthog-migration-deep-dive

# PostHog Migration Deep Dive ## Current State !`npm list posthog-js posthog-node 2>/dev/null | grep posthog || echo 'No PostHog SDK found'` !`npm list @segment/analytics-node mixpanel @google-analytics/data 2>/dev/null | grep -E "segment|mixpanel|google" || echo 'No competitor SDKs found'` ## Overview Migrate from Google Analytics, Mixpanel, Amplitude, or Segment to PostHog using a dual-write strategy (send events to both old and new platforms) followed by gradual traffic shifting. PostHog's capture API accepts events in a format similar to Segment's track/identify calls, making migration straightforward. ## Migration Types | Source | Complexity | Duration | Key Challenge | |--------|-----------|----------|---------------| | Google Analytics (GA4) | Medium | 2-4 weeks | Event model is fundamentally different | | Mixpanel | Low | 1-2 weeks | Very similar event model | | Amplitude | Low | 1-2 weeks | Similar event model | | Segment | Low | 1 week | PostHog has a Segment destination | | Custom analytics | Medium | 2-4 weeks | Depends on current implementation | ## Instructions ### Step 1: Event Name Mapping ```typescript // migration/event-map.ts // Map old event names to PostHog event taxonomy const EVENT_MAP: Record<string, string> = { // Mixpanel → PostHog 'Sign Up': 'user_signed_up', 'Login': 'user_logged_in', 'Page View': '$pageview', 'Button Click': 'button_clicked', 'Purchase': 'payment_completed', 'Subscription Started': 'subscription_started', ...