Frontend Development Guidelines

This document describes various guidelines to ensure consistency and quality across GitLab’s frontend team.


GitLab is built on top of Ruby on Rails using Haml and also a JavaScript based Frontend with Vue.js. Be wary of the limitations that come with using Hamlit. We also use SCSS and plain JavaScript with modern ECMAScript standards supported through Babel and ES module support through webpack.

Working with our frontend assets requires Node (v10.13.0 or greater) and Yarn (v1.10.0 or greater). You can find information on how to install these on our installation guide.

Browser Support

For our currently-supported browsers, see our requirements.

Use BrowserStack to test with our supported browsers. Sign in to BrowserStack with the credentials saved in the Engineering vault of GitLab’s shared 1Password account.


Current high-level frontend goals are listed on Frontend Epics.


High-level guidelines for contributing to GitLab.

Development Process

How we plan and execute the work on the frontend.


How we go about making fundamental design decisions in GitLab’s frontend team or make changes to our frontend development guidelines.


How we write frontend tests, run the GitLab test suite, and debug test related issues.

Pajamas Design System

Reusable components with technical and usage guidelines can be found in our Pajamas Design System.

Design Patterns

Common JavaScript design patterns in GitLab’s codebase.

Vue.js Best Practices

Vue specific design patterns and practices.


Vuex specific design patterns and practices.


Axios specific practices and gotchas.


How to use GraphQL.

Icons and Illustrations

How we use SVG for our Icons and Illustrations.


General information about frontend dependencies and how we manage them.


Read the frontend’s FAQ for common small pieces of helpful information.

Style Guides

See the relevant style guides for our guidelines and for information on linting:

  • JavaScript. Our guide is based on the excellent Airbnb style guide with a few small changes.
  • SCSS: our SCSS conventions which are enforced through scss-lint.
  • HTML. Guidelines for writing HTML code consistent with the rest of the codebase.
  • Vue. Guidelines and conventions for Vue code may be found here.


Our code is automatically formatted with Prettier to follow our guidelines. Read our Tooling guide for more detail.


Best practices for monitoring and maximizing frontend performance.


Frontend security practices.


Our accessibility standards and resources.

Internationalization (i18n) and Translations

Frontend internationalization support is described in this document. The externalization part of the guide explains the helpers/methods available.