posthog-migration-deep-dive

name	posthog-migration-deep-dive
description	Migrate to PostHog from Google Analytics, Mixpanel, Amplitude, or Segment. Covers dual-write strategy, historical data import, event name mapping, identity resolution, and feature flag based traffic shifting. Trigger: "migrate posthog", "posthog migration", "switch to posthog", "posthog from mixpanel", "posthog from GA", "posthog replatform".
allowed-tools	Read, Write, Edit, Bash(npm:*), Bash(node:*), Bash(kubectl:*)
version	1.12.0
license	MIT
author	Jeremy Longshore <[e-mail]>
tags	["saas","posthog","migration"]
compatibility	Designed for Claude Code

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

// 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',

  
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};


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