PostHog vs Mixpanel vs Amplitude: Choosing Your Analytics Stack

#webdev #analytics #saas #startup

PostHog vs Mixpanel vs Amplitude: Choosing Your Analytics Stack

Product analytics tells you what users are actually doing — not what you think they're doing. Here's how to pick the right tool.

What Product Analytics Gives You

Funnel analysis: where do users drop off in your flow?
Retention curves: are users coming back?
Feature adoption: is anyone using that thing you built?
Session recordings: watch real users interact with your product
A/B test results: which version converts better?

PostHog: The Open-Source Choice

Best for: startups, privacy-conscious products, technical teams

import posthog from 'posthog-js';

posthog.init(process.env.NEXT_PUBLIC_POSTHOG_KEY!, {
  api_host: 'https://app.posthog.com',
  capture_pageview: false, // Manual control
});

// Track events
posthog.capture('checkout_started', {
  plan: 'pro',
  source: 'pricing_page',
  mrr: 99,
});

// Identify users
posthog.identify(user.id, {
  email: user.email,
  plan: user.plan,
  createdAt: user.createdAt,
});

Pros: free up to 1M events/month, open-source, feature flags + A/B testing included, session recordings, GDPR-friendly self-hosting option.

Cons: UI is less polished than Mixpanel/Amplitude.

Mixpanel: Best-in-Class Funnels

Best for: products where funnel optimization is critical (e-commerce, growth teams)

mixpanel.track('Purchase Completed', {
  'Product': 'AI SaaS Starter',
  'Revenue': 99,
  'Currency': 'USD',
});

Pros: best funnel analysis UX, fast queries, excellent mobile SDKs.
Cons: expensive at scale ($25/month up to 25K MTU, then scales quickly).

Amplitude: For Data Teams

Best for: companies with dedicated data analysts, complex behavioral queries

Pros: most powerful query engine, best for large data volumes, Amplitude Compass for causal analysis.
Cons: steeper learning curve, overkill for early-stage.

My Recommendation

Stage	Tool
Pre-PMF	PostHog free tier
$10K-100K MRR	PostHog (scale or self-host)
Growth stage	Mixpanel or continue PostHog
Enterprise	Amplitude

Start with PostHog. It's free, full-featured, and you can migrate later if needed. The switching cost is low (just update your tracking calls).

What to Track From Day 1

// Core funnel events
posthog.capture('signup_completed');
posthog.capture('onboarding_step_completed', { step: 'profile' });
posthog.capture('first_core_action_completed'); // Your 'aha moment'
posthog.capture('subscription_started', { plan, mrr });
posthog.capture('subscription_cancelled', { reason, plan, tenure_days });