PostHog
Product analytics, session replay, feature flags, and A/B testing — all in one open-source tool
PostHog is what you get when developers build analytics for developers. Instead of paying for Mixpanel (analytics) + FullStory (session replay) + LaunchDarkly (feature flags) + Optimizely (A/B tests), PostHog bundles all four into one platform. And the free tier is 1 million events per month — enough for most startups to run for months without paying.
The honest downside is complexity. PostHog can do a lot, and figuring out what to track and how to set up useful dashboards takes real effort. If you just want page views and referrer data, Plausible or Fathom is simpler. If you want to understand how users actually move through your product, PostHog is worth the setup time.
What's good
- 1 million free events/month covers most startups for a long time
- Replaces 4+ separate tools (analytics, session replay, feature flags, A/B testing)
- Self-hosting option if you need to keep data on your own servers
Watch out for
- Steep learning curve — the sheer number of features can be overwhelming at first
- Setting up meaningful dashboards takes time and thought
- Self-hosted version requires real infrastructure to run