• Get started
• Processes
• UX and Frontend guides
• Backend guides
• Performance guides
• Database guides
  • Tooling
  • Migrations
  • Debugging
  • Best practices
  • Case studies
• Integration guides
• Testing guides
• Refactoring guides
• Documentation guides
• Internationalization (i18n) guides
• Telemetry guides
• Experiment Guide
• Build guides
• Compliance
• Go guides
• Shell Scripting guides
• Domain-specific guides
• Other Development guides
• Other GitLab Development Kit (GDK) guides

Contributor and Development Docs

Get started

• Set up GitLab’s development environment with GitLab Development Kit (GDK)
• GitLab contributing guide
  • Issues workflow. For information on:
    • Issue tracker guidelines.
    • Triaging.
    • Labels.
    • Feature proposals.
    • Issue weight.
    • Regression issues.
    • Technical or UX debt.
  • Merge requests workflow. For information on:
    • Merge request guidelines.
    • Contribution acceptance criteria.
    • Definition of done.
    • Dependencies.
  • Style guides
  • Implement design & UI elements
• GitLab Architecture Overview
• Rake tasks for development

Processes

Must-reads:

• Code review guidelines for reviewing code and having code reviewed
• Database review guidelines for reviewing database-related changes and complex SQL queries, and having them reviewed
• Secure coding guidelines
• Pipelines for the GitLab project

Complementary reads:

• GitLab core team & GitLab Inc. contribution process
• Security process for developers
• Guidelines for implementing Enterprise Edition features
• Danger bot
• Generate a changelog entry with bin/changelog
• Requesting access to Chatops on GitLab.com (for GitLab team members)

UX and Frontend guides

• GitLab Design System for building GitLab with existing CSS styles and elements
• Frontend guidelines
• Emoji guide

Backend guides

• GitLab utilities
• Issuable-like Rails models
• Logging
• API styleguide Use this styleguide if you are contributing to the API
• GraphQL API styleguide Use this styleguide if you are contributing to the GraphQL API
• Sidekiq guidelines for working with Sidekiq workers
• Working with Gitaly
• Manage feature flags
• Licensed feature availability
• View sent emails or preview mailers
• Shell commands in the GitLab codebase
• Gemfile guidelines
• Pry debugging
• Sidekiq debugging
• Accessing session data
• Gotchas to avoid
• Avoid modules with instance variables if possible
• How to dump production data to staging
• Working with the GitHub importer
• Import/Export development documentation
• Test Import Project
• Elasticsearch integration docs
• Working with Merge Request diffs
• Kubernetes integration guidelines
• Permissions
• Prometheus
• Guidelines for reusing abstractions
• DeclarativePolicy framework
• How Git object deduplication works in GitLab
• Geo development
• Routing
• Repository mirroring
• Git LFS
• Developing against interacting components or features
• File uploads
• Auto DevOps development guide
• Mass Inserting Models
• Value Stream Analytics development guide
• Issue types vs first-class types
• Application limits
• Redis guidelines
• Rails initializers
• Code comments
• Renaming features

Performance guides

• Instrumentation for Ruby code running in production environments
• Performance guidelines for writing code, benchmarks, and certain patterns to avoid
• Merge request performance guidelines for ensuring merge requests do not negatively impact GitLab performance
• Profiling a URL, measuring performance using Sherlock, or tracking down N+1 queries using Bullet

Database guides

Tooling

• Understanding EXPLAIN plans
• explain.depesz.com for visualising the output of EXPLAIN
• pgFormatter a PostgreSQL SQL syntax beautifier

Migrations

• What requires downtime?
• SQL guidelines for working with SQL queries
• Migrations style guide for creating safe SQL migrations
• Testing Rails migrations guide
• Post deployment migrations
• Background migrations
• Swapping tables
• Deleting migrations

Debugging

• Tracing the source of an SQL query using query comments with Marginalia
• Tracing the source of an SQL query in Rails console using Verbose Query Logs

Best practices

• Adding database indexes
• Foreign keys & associations
• Single table inheritance
• Polymorphic associations
• Serializing data
• Hash indexes
• Storing SHA1 hashes as binary
• Iterating tables in batches
• Insert into tables in batches
• Ordering table columns
• Verifying database capabilities
• Database Debugging and Troubleshooting
• Query Count Limits
• Creating enums

Case studies

• Database case study: Filtering by label
• Database case study: Namespaces storage statistics

Integration guides

• Jira Connect app
• Security Scanners
• Secure Partner Integration
• How to run Jenkins in development environment

Testing guides

• Testing standards and style guidelines
• Frontend testing standards and style guidelines

Refactoring guides

• Refactoring guidelines

Documentation guides

• Writing documentation
• Documentation styleguide
• Markdown

Internationalization (i18n) guides

• Introduction
• Externalization
• Translation

Telemetry guides

• Introduction
• Frontend tracking guide
• Backend tracking guide

Experiment Guide

• Introduction

Build guides

• Building a package for testing purposes

Compliance

• Licensing for ensuring license compliance

Go guides

• Go Guidelines

Shell Scripting guides

• Shell scripting standards and style guidelines

Domain-specific guides

• CI/CD development documentation

Other Development guides

• Defining relations between files using projections
• Reference processing

Other GitLab Development Kit (GDK) guides

• Run full Auto DevOps cycle in a GDK instance
• Using GitLab Runner with GDK
• Using the Web IDE terminal with GDK