Project structure

Note: This page refers to our main product repository, not our website.

Directory tree

.
├── bin              # Shell scripts for building, testing, and running PostHog
├── common           # Shared code: PostHog SQL parser, HogVM, shared UI packages
├── ee               # Enterprise platform package features (separate license)
├── frontend         # React/TypeScript frontend application
│   └── src
│       └── layout   # App layout components (navigation, sidebars)
│       └── lib      # Reusable components and utilities
│       └── scenes   # Page-specific components
│       └── queries  # Query builder components
│       └── toolbar  # PostHog Toolbar code
├── livestream       # Golang service for live events API
├── playwright       # End-to-end tests using Playwright
├── plugin-server    # Node.js service for event ingestion and plugins
├── posthog          # Django backend application
│   └── api          # REST API endpoints
│   └── clickhouse   # ClickHouse database interactions
│   └── hogql        # HogQL query language implementation
│   └── models       # Django ORM models
│   └── tasks        # Celery background tasks
├── products         # Product-specific code (vertical slices)
└── rust             # High-performance Rust services

*Selected subdirectories only

Key directories

frontend

The PostHog web application, built with React and TypeScript. Uses Kea for state management.

• src/lib – Reusable components and utilities
• src/scenes – Page-specific components organized by feature
• src/queries – Query builder and data visualization components
• src/toolbar – Code for the PostHog Toolbar

posthog

The Django backend application. Key subdirectories:

• api – REST API endpoints and serializers
• clickhouse – ClickHouse schema definitions and migrations
• hogql – PostHog SQL query language compiler and executor
• models – Django ORM models (PostgreSQL)
• tasks – Celery background tasks

products

Product-specific code organized as vertical slices. Each product folder contains its own backend (Django app), frontend (React), and optionally shared code. This structure allows features to evolve independently.

See the products README for detailed conventions.

plugin-server

Node.js service responsible for:

• Event ingestion and processing
• Running plugins and data pipelines
• Webhook delivery

rust

High-performance Rust services including:

• capture – Event capture endpoint
• feature-flags – Feature flag evaluation
• cymbal – Error tracking symbolication
• Various workers and utilities

common

Shared code used across the codebase:

• hogql_parser – PostHog SQL parser (C++)
• hogvm – Hog virtual machine
• tailwind – Shared Tailwind configuration

ee

Enterprise edition licensed features. This directory has a separate license - not MIT. For 100% FOSS code, see PostHog/posthog-foss.

playwright

End-to-end tests using Playwright. Tests live in the e2e/ subdirectory.

livestream

Golang service powering the live events feed in the Activity tab.