Skip to content

Implementing CODEOWNERS for Pull Request Automation

🧩 This hands-on lab walks you through adding a CODEOWNERS file to automatically assign reviewers and enforce ownership rules on pull requests.

1. Using CODEOWNERS

  • CODEOWNERS is a file that allows you to define individuals or teams responsible for specific parts of your codebase.
  • When changes are made to those areas, the designated code owners are automatically requested for review.
  • This helps ensure that the right people are reviewing changes to critical parts of the code.
  • CODEOWNERS can also be used to enforce review policies, such as requiring approval from code owners before merging.

How CODEOWNERS Works

  • Automatically assigns reviewers based on file changes
  • Ensures domain experts review relevant code
  • Can be combined with branch protection rules
  • Supports teams and individual users

  • Create .github/CODEOWNERS in your repository:

    # Global owners
* @username @team-name

# Frontend code
/src/components/ @frontend-team
/src/styles/ @design-team

# Backend code
/api/ @backend-team
/database/ @backend-team @database-admin

# Infrastructure
/.github/ @devops-team
/docker/ @devops-team

2. CODEOWNERS - Files location

GitHub search for the first matching file in following order:

  1. .github/CODEOWNERS
  2. CODEOWNERS in the repository root
  3. docs/CODEOWNERS

Tip

Recommended: Use .github/CODEOWNERS for consistency with other meta files (workflows, templates).

3. CODEOWNERS - Pattern

Pattern Type Example Matches
Single file README.md Exact file
Directory (recursive) src/ Everything under src/
Specific extension *.md All Markdown files
Nested path app/api/ Files in that folder & subfolders
Escaping # \#file.txt File literally named #file.txt
Comment line # owners of infra Ignored
Last match wins Later entries override Use ordering intentionally

4. CODEOWNERS - Example

  • Create directory (if needed):

    mkdir -p .github

  • Add file .github/CODEOWNERS:

    # Global ownership (fallback)
* nirgeier@gmail.com

# Documentation
/docs/ @your-org/docs-writers
*.md   @your-org/docs-writers

# Frontend code
/src/components/ @your-org/frontend-team
/src/styles/ @your-org/design-team

###
###... Any other paths or file types
###

  • Add to git & push:

    git add .github/CODEOWNERS
git commit -m "Add initial CODEOWNERS file"
git push origin main

5. CODEOWNERS - Enable

If you have not enabled branch protection yet:

  1. Go to: Repository → Settings → Rules → Rulesets (or Branches > Branch protection)
  2. Create / Edit your ruleset targeting main
  3. Enable the following
    • Require a pull request before merging
    • Require approvals: set to 1 (or more)
    • Require review from Code Owners
    • Dismiss stale approvals (recommended)
    • Require conversation resolution
  4. Save / Activate the ruleset

Code Owners Settings

6. CODEOWNERS - Verify (Test)

  • Open a pull request
  • In the PR sidebar you should see:
  • Reviewers automatically populated with teams/users from matching patterns.

Auto CODEOWNERS

7. CODEOWNERS - Checklist

Use this checklist to validate success:

  • CODEOWNERS exists at .github/CODEOWNERS
  • Global * rule defined
  • At least one team + one individual user referenced (optional)
  • Branch protection requires Code Owner review
  • Test PR auto-assigned reviewers
  • Specific path override tested