GitLab Project Structure
The comprehensive DevOps platform. GitLab is a classic and massive Ruby on Rails monolith that has successfully scaled to the enterprise level, featuring an increasingly sophisticated Vue.js frontend and a highly modular internal structure.
Updated 2025-12-30
Project Directory
Repository Info
- Repository-gitlabhq/gitlabhq
- Stars-23k+
- License-MIT (CE) / Proprietary (EE)
- Last Analyzed-December 2025
Tech Stack
- Backend-Ruby on Rails
- Frontend-Vue.js
- Language-Ruby / JavaScript
- Database-PostgreSQL
- Background-Sidekiq & Redis
- Storage-Gitaly (Git access service)
Architecture Notes
GitLab is one of the most significant Ruby on Rails monoliths in the world. It follows a highly disciplined MVC architecture, with much of its domain logic increasingly housed in the lib/ directory or internal gems/ to keep the main Rails app manageable. The frontend has been undergoing a massive transition to Vue.js, following a component-driven approach. To handle Git operations at scale, they developed 'Gitaly', a specialized Go service that the Rails app communicates with, showing how to selectively break apart a monolith for performance.
Key Directories
- app/-The primary Rails application directory, housing the MVC structure and frontend assets
- lib/-The engine room where much of GitLab's specialized core logic resides
- config/-Manages the vast array of settings required for the GitLab ecosystem
- db/-Defines the complex data model required for source control and CI/CD
Why This Structure?
GitLab is the ultimate reference for large-scale Ruby on Rails development. It demonstrates how to maintain a massive monolith over many years while continuously modernizing the frontend and scaling the backend. It's a required study for anyone interested in enterprise software architecture and the DevOps lifecycle.