Don't confuse product analytics with web analytics
Web analytics (GA4, Plausible) answers: who visited my marketing site? Product analytics (Mixpanel, Amplitude, PostHog) answers: who's using my product, doing what, and where are they dropping off? These are different problems. Don't try to solve one with the other.
1. PostHog — Best overall in 2026
PostHog has compounded its lead by bundling product analytics, session replay, feature flags, A/B testing, and a CDP into one platform — with a generous free tier (1M events/month) and self-hostable option. For most product teams under 100 engineers, it's the right default in 2026.
2. Amplitude — Best at scale
Amplitude is still where serious product analytics happens at the enterprise tier. Its retention curves, behavioural cohorts, and pathfinder analyses are best-in-class. But pricing scales hard once you exceed the free tier — be ready for sticker shock.
3. Mixpanel — Still credible
Mixpanel was the original event-based product analytics tool and remains a credible pick. The UI is cleaner than Amplitude's. Pricing is also more friendly at the lower end. The reason it's slipping is feature parity with PostHog at a worse free tier.
4. Hotjar — Best for session replay only
If all you want is session recordings and heatmaps for your marketing site or app, Hotjar is fine. But pairing Hotjar with a separate product analytics tool means duplicate instrumentation — PostHog includes session replay natively now, which is the better unified play.
5. GA4 — Use it for your marketing site only
Google Analytics 4 is a marketing-site analytics tool. Acquisition channels, landing page performance, conversion goals — that's its zone. Trying to track product events in GA4 is a recipe for missing data, sampling issues, and confused dashboards.
How to pick
- Just need marketing-site numbers → GA4 or Plausible
- Pre-seed to Series A product team → PostHog (free tier covers you)
- Series B+ doing serious experimentation → Amplitude
- Just need session replay on marketing site → Hotjar (or PostHog)
The under-rated thing
Whichever tool you pick: spend a day defining your event taxonomy before you start instrumenting. Inconsistent event names are the silent killer of product analytics. The best tool with bad data is worse than the worst tool with disciplined naming.