PostHog vs Google Analytics: product analytics versus web analytics
This comparison gets searched constantly and answered lazily. GA4 is a web-analytics and marketing-attribution tool. PostHog is a product-analytics platform. Most teams that ask this question actually need both, pointed at different jobs.
Why this comparison is usually the wrong question
GA4 and PostHog are frequently compared as if they compete for the same job. They mostly do not. GA4 is built for marketing attribution, channel performance, and site-wide traffic reporting - the questions a marketing team asks. PostHog is built for product analytics - the questions a product team asks about what users do after they land on the product.
Free at most volumes, paid tier (GA4 360) at enterprise scale
Usage-based across products, free tier included
Where they actually overlap
The genuine overlap is event tracking and basic funnel analysis - both can technically track a signup or a purchase event. But GA4's strength is aggregating that across marketing channels and campaigns; PostHog's strength is connecting that event to everything the user does afterward inside the product, plus feature flags and replay to investigate why.
The practical setup we usually recommend
Keep GA4 (or an equivalent web-analytics tool) owning marketing attribution and channel reporting. Bring in PostHog for in-product behavioral analytics once there is a product to analyze usage in. The two systems answering different questions, wired together at the events that matter (signup, activation, conversion) rather than treated as competing single sources of truth, is the setup we implement most often.
Frequently Asked Questions
Can PostHog replace GA4 entirely?
It depends what GA4 is being used for. If it's mainly marketing attribution, channel reporting, and site-wide traffic analysis, GA4's purpose-built tooling for that is hard to fully replace with a product-analytics platform. If it's being used for in-product behavioral analysis, PostHog is usually the better-fit tool for that specific job.
Why would a team run both?
GA4 for marketing attribution and top-of-funnel traffic reporting, PostHog for what happens after someone signs up or converts - feature usage, retention, funnels inside the product. Different questions, different tools.
Is PostHog free like GA4?
PostHog offers a free usage tier, but its pricing model and GA4's are structured differently - check both current pricing pages rather than assuming parity.
Does PostHog handle cookie consent the way GA4 does?
Both need to be wired into your consent-management setup; the specific consent-mode mechanics differ by platform and should be verified against current documentation rather than assumed identical.
Figuring out what GA4 and PostHog should each own?
We scope the split - marketing attribution versus product analytics - and wire the shared events between them.