Zulip Project Structure
The threaded team chat app. A massive Python/Django codebase known for its high code quality, custom frontend, and unique threading model.
Updated 2025-12-30
Project Directory
zulip/
zerver/
Main Django App
models.py
Data models (Stream, Topic, Message)
views/
API Endpoints
messages.py
users.py
actions/
Business Logic (Service Layer)
tornado/
Real-time push system
web/
Frontend Web App
src/
TypeScript source
templates/
Handlebars templates
styles/
CSS
templates/
Server-side templates (Jinja2)
puppet/
Infrastructure (Puppet)
manage.py
Django CLI
requirements.txt
Python Deps
Repository Info
- Repository-zulip/zulip
- Stars-20k+
- License-Apache-2.0
- Last Analyzed-December 2025
Tech Stack
- Backend-Python (Django)
- Real-time-Python (Tornado)
- Frontend-TypeScript (Custom)
- Database-PostgreSQL
- Cache-Redis + Memcached
- Queue-RabbitMQ
Architecture Notes
Zulip uses a hybrid architecture. **Django** (zerver) handles the REST API and database interactions. **Tornado** runs purely as an event queue bridge, holding open long-polling/WebSocket connections to push events from RabbitMQ to clients. This allows Django to remain synchronous and simple.
Key Directories
- zerver/-The core Django application. It contains an
actions/directory which acts as a 'Service Layer', encapsulating business logic separately from Views. - web/src/-The frontend is a single-page app but *not* React/Vue. It uses a custom architecture built on jQuery and Handlebars, now migrated to TypeScript. It's optimized for rendering massive message lists.
- puppet/-Zulip includes its own configuration management. The
zulipPuppet module defines exactly how to deploy the server, enforcing a strict production environment.
Why This Structure?
Zulip is a masterpiece of optimization and code organization. It handles thousands of concurrent users and millions of messages efficiently. Its 'Service Layer' pattern in Django (zerver/actions) is a model for how to structure large Python web apps.
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