In-app, website, link, and email surveys feed one open-source experience management platform: Formbricks. Its distinguishing strength is targeted in-app research: a JavaScript SDK triggers surveys on user events and attributes, with segmentation rules like "power users who have not seen a survey in 10 days," so questions reach the right cohort at the right moment instead of a mass email blast. The no-code editor offers 20+ question types including NPS, CSAT, CES, matrix, ranking, and file upload, with skip logic, conditional branching, best-practice templates, and full brand theming. Responses feed built-in analytics with summaries and CSV/JSON export, and integrations push data to Slack, Notion, Google Sheets, Airtable, Zapier, and n8n, with webhooks and an open API on every tier. Because self-hosted surveys load from your own domain rather than a blacklisted third-party script host, ad blockers do not suppress them - in-app surveys reach users that Hotjar-style tools silently miss, which measurably raises response rates. Self-hosting also removes the third-party sub-processor from your privacy policy entirely: survey responses often contain PII, and keeping them on your own server matters for GDPR-sensitive and regulated industries. The Community Edition has no response caps or tier-gated features, so core functionality and your data stay accessible regardless of any subscription. Next.js on PostgreSQL, AGPLv3.

With over 37,000 GitHub stars and used by teams at Y Combinator, Airbus, and Phantom, PostHog replaces an entire stack of paid analytics tools — Mixpanel, Amplitude, Heap, LaunchDarkly, Hotjar, and Google Analytics — with a single open-source platform where every tool shares a common event layer and user context. Product analytics captures events automatically or via manual instrumentation with HogQL (SQL) access for custom queries, while web analytics provides GA-like dashboards for traffic, conversions, and Core Web Vitals. Session replay records user interactions with DOM snapshots and network waterfall analysis, linking directly to errors and feature flag exposures. Feature flags safely roll out changes to specific cohorts with multivariate support and instant rollback, while experiments run A/B tests with automatic Bayesian significance calculations and revenue attribution. Error tracking captures stack traces linked to session replays and user properties for immediate reproduction context. AI observability monitors LLM generations, traces, token usage, latency, and costs across model versions. The managed data warehouse syncs 120+ external sources including Stripe, Postgres, Salesforce, and HubSpot alongside product events, queryable through a unified SQL editor. An MCP server enables AI agents in Cursor, Claude Code, or VS Code to query analytics and execute SQL directly. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Used by over 3,000 organizations including Dropbox, Khan Academy, Sony, Pepsi, Wikipedia, and Mistral, GrowthBook is the open-source experimentation platform that handles over 100 billion feature flag evaluations daily across its cloud and self-hosted deployments. Feature flags support advanced targeting with user attributes, gradual percentage rollouts, prerequisite dependencies, and scheduled launches, with both client and server SDKs evaluating flags locally from a cached payload for sub-millisecond performance with zero network calls per check. The warehouse-native architecture queries experiment results directly from 11 data sources including BigQuery, Snowflake, Databricks, Redshift, ClickHouse, Mixpanel, and PostgreSQL, eliminating duplicate data pipelines. The statistics engine implements CUPED variance reduction, sequential testing, Bayesian analysis, post-stratification, multi-armed bandits, and sample ratio mismatch checks with fully open-source methodology. Product analytics provides dashboards with funnels, retention cohorts, and event-based tracking shareable across teams. Twenty-four SDKs cover React, Next.js, Node.js, Python, Go, Ruby, PHP, Java/Kotlin, Swift, C#/.NET, Rust, Elixir, Angular, and edge runtimes including Cloudflare Workers, Fastly Compute, and Lambda@Edge. The MCP server and REST API enable AI coding agents to create features, start experiments, and manage stale flags programmatically. Self-hosting deploys via Docker Compose with MongoDB, or via Helm charts on Kubernetes, with the same codebase powering both open-source and managed cloud offerings. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Backed by 12,400+ GitHub stars and positioned as the self-hosted alternative to FullStory and Hotjar, OpenReplay delivers the open-source session replay platform that keeps every byte of user behavior data on your own infrastructure. The JavaScript tracker captures pixel-perfect recordings of clicks, scrolls, form inputs, and navigation with automatic sensitive data masking, while simultaneously logging network requests, console errors, JavaScript exceptions, and Redux, VueX, MobX, NgRx, Pinia, and Zustand store state changes for complete technical context. DevTools mode reconstructs each session with full stack traces, GraphQL queries from Apollo and Relay, Fetch and Axios request payloads, CPU and memory metrics, and page speed waterfall charts — effectively giving developers a browser inspector tied to any user session. Product analytics surfaces conversion funnels, user journeys, click heatmaps, web vitals trends, and retention cohorts without requiring custom instrumentation. Co-browsing connects support agents to live user sessions with cursor control and WebRTC audio, enabling real-time assistance without third-party screen-sharing software. Integrations push session context into Sentry, Datadog, CloudWatch, Stackdriver, and Elastic for front-to-back debugging. Feature flags enable gradual rollouts with session-level targeting. The platform deploys to any cloud via Docker and Kubernetes with auto-scaling ingestion handling up to 50,000 sessions per month on the open-source edition. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPLv3 licensed.

Known as the open-source Mixpanel alternative that respects user privacy, OpenPanel delivers a unified web and product analytics platform combining Mixpanel's behavioral analysis with the simplicity of Plausible and full data ownership through self-hosting. Cookieless tracking eliminates consent banners entirely while still capturing events, page views, sessions, user journeys, funnels, retention cohorts, and custom properties with full GDPR compliance by design. The 2.3 KB async script loads without blocking page rendering, and 16 official SDKs cover Next.js, React, Vue, Astro, Remix, Nuxt, Angular, Svelte, React Native, Swift, Kotlin, Python, PHP, Laravel, Express, and REST API for custom integrations. Real-time dashboards display live visitor counts, active sessions, and event streams as they happen. Custom chart builders create tailored visualizations from any tracked event with breakdowns by property, time period, and user segment. Session replay reconstructs individual user journeys showing every page visited, event triggered, and interaction recorded. Funnel analysis identifies conversion drop-offs with step-by-step breakdown and property filtering. Retention analysis measures how often users return with customizable time windows and cohort comparisons. A/B testing and variant tracking enable experiment measurement directly within the platform. Event notifications alert when specific events occur or thresholds are crossed. The self-hosted deployment uses Docker Compose with ClickHouse for high-speed analytical queries, PostgreSQL for metadata, and Redis for real-time processing — deployable on any VPS or Kubernetes cluster. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.