You can use a CODEOWNERS file to define individuals or teams that are responsible for code in a repository.
People with admin or owner permissions can set up a CODEOWNERS file in a repository. The people you choose as code owners must have write permissions for the repository.
Code owners are automatically requested for review when someone opens a pull request that modifies code that they own. When someone with admin or owner permissions has enabled required reviews, they also can optionally require approval from a code owner before the author can merge a pull request in the repository.
CODEOWNERS file location
To use a CODEOWNERS file, create a new file called CODEOWNERS in the root, docs/, or .github/ directory of the repository, in the branch where you'd like to add the code owners.
Each CODEOWNERS file assigns the code owners for a single branch in the repository. Thus, you can assign different code owners for different branches, such as @octo-org/codeowners-team for a code base on the master branch and @octocat for a GitHub Pages site on the gh-pages branch.
For code owners to receive review requests, the CODEOWNERS file must be on the base branch of the pull request. For example, if you assign @octocat as the code owner for .js files on the gh-pages branch of your repository, @octocat will receive review requests when a pull request with changes to .js files is opened between the head branch and gh-pages.
CODEOWNERS syntax
A CODEOWNERS file uses a pattern that follows the same rules used in gitignore files. The pattern is followed by one or more GitHub usernames or team names using the standard @username or @org/team-name format. You can also refer to a user by an email address that has been added to their GitHub account, for example user@example.com.
CODEOWNERS file example:
# This is a comment.
# Each line is a file pattern followed by one or more owners.
# These owners will be the default owners for everything in
# the repo. Unless a later match takes precedence,
# @global-owner1 and @global-owner2 will be requested for
# review when someone opens a pull request.
* @global-owner1 @global-owner2
# Order is important; the last matching pattern takes the most
# precedence. When someone opens a pull request that only
# modifies JS files, only @js-owner and not the global
# owner(s) will be requested for a review.
*.js @js-owner
# You can also use email addresses if you prefer. They'll be
# used to look up users just like we do for commit author
# emails.
*.go docs@example.com
# In this example, @doctocat owns any files in the build/logs
# directory at the root of the repository and any of its
# subdirectories.
/build/logs/ @doctocat
# The `docs/*` pattern will match files like
# `docs/getting-started.md` but not further nested files like
# `docs/build-app/troubleshooting.md`.
docs/* docs@example.com
# In this example, @octocat owns any file in an apps directory
# anywhere in your repository.
apps/ @octocat
# In this example, @doctocat owns any file in the `/docs`
# directory in the root of your repository.
/docs/ @doctocat
