posthog-analytics

PostHog Analytics Skill

Load with: base.md + [framework].md

For implementing product analytics with PostHog - event tracking, user identification, feature flags, and project-specific dashboards.

Sources: PostHog Docs | Product Analytics | Feature Flags

---

Philosophy

Measure what matters, not everything.

Analytics should answer specific questions:

• Are users getting value? (activation, retention)
• Where do users struggle? (funnels, drop-offs)
• What features drive engagement? (feature usage)
• Is the product growing? (acquisition, referrals)

Don't track everything. Track what informs decisions.

---

Installation

Next.js (App Router)

npm install posthog-js

// lib/posthog.ts
import posthog from 'posthog-js';

export function initPostHog() {
  if (typeof window !== 'undefined' && !posthog.__loaded) {
    posthog.init(process.env.NEXT_PUBLIC_POSTHOG_KEY!, {
      api_host: process.env.NEXT_PUBLIC_POSTHOG_HOST || 'https://us.i.posthog.com',
      person_profiles: 'identified_only', // Only create profiles for identified users
      capture_pageview: false, // We'll handle this manually for SPA
      capture_pageleave: true,
      loaded: (posthog) => {
        if (process.env.NODE_ENV === 'development') {
          posthog.debug();
        }
      },
    });
  }
  return posthog;
}

export { posthog };

// app/providers.tsx
'use client';

import { useEffect } from 'react';
import { usePathname, useSearchParams } from 'next/navigation';
import { initPostHog, posthog } from '@/lib/posthog';

export function PostHogProvider({ children }: { children: React.ReactNode }) {
  const pathname = usePathname();
  const searchParams = useSearchParams();

  useEffect(() => {
    initPostHog();
  }, []);

  // Track pageviews
  useEffect(() => {
    if (pathname) {
      let url = window.origin + pathname;
      if (searchParams.toString()) {
        url += `?${searchParams.toString()}`;
      }
      posthog.capture('$pageview', { $current_url: url });
    }
  }, [pathname, searchParams]);

  return <>{children}</>;
}