PostHog

PostHog is an open-source product engineering platform that bundles event-based product analytics, session replay, feature flags, A/B experimentation, surveys, error tracking, and a lightweight CDP into a single deployable stack rather than a patchwork of separate SaaS tools. Its autocapture library records clicks and pageviews without manual instrumentation, while a ClickHouse-backed query engine, exposed through the custom HogQL dialect, powers funnels, retention curves, and cohort analysis at scale. Teams can either use the generously free-tiered PostHog Cloud or self-host the open-source core with Docker for full data ownership, a common choice for companies in regulated industries. The core codebase is MIT licensed, while a smaller "ee" directory containing enterprise features like SSO and advanced permissions sits under a separate commercial license.