PostHog

PostHog is a complete product-analytics platform that combines event tracking, session replay, feature flags, and A/B testing in one self-hostable product — replacing what would normally be several separate SaaS tools. It is built around autocapture and custom events for product teams rather than marketing page views. Data ownership is a core difference: you can run it on your own infrastructure instead of sending usage data to a vendor.

PostHog can be deployed with Docker and uses ClickHouse for analytics storage alongside Postgres and Redis, so self-hosting means running a fairly substantial stack. It captures events from web, mobile, and server-side sources via SDKs for JavaScript, Python, Go, and most major languages, and exposes a full API and webhooks. If you prefer not to run it yourself, PostHog also offers a managed cloud option.

Very little to start — PostHog's autocapture records clicks, pageviews, and input events out of the box, so you can begin collecting product data with minimal setup. When you need more, you add custom event tracking, build funnels and user paths, run experiments, and control feature rollouts with targeted flags. With 37k+ GitHub stars and an active contributor community, it is one of the most mature open-source product-analytics stacks.