Local development

For GitHub internal use only

When you are working with the github/github codebase, you can link Primer CSS modules with your local development environment using the Primerize script. This will allow you to make changes to Primer CSS and see them reflected on github.localhost without the overhead of pulling in alpha releases of a package.


  1. Working with github/github on the latest codebase.
  2. Cloned down latest version of primer/primer.
  3. The github/github folder and the primer/primer folder must share the same parent folder.


├── github
└── primer

Linking to your local Primer CSS repository

In your terminal start the server with the environment variable LOCAL_PRIMER=1. For example.

> LOCAL_PRIMER=1 script/server

When the variable is present, the script will check for linked local Primer CSS packages. If it’s not linked, then it will proceed to link the Primer CSS packages in ../primer to your GitHub application. When the server starts with successfully linked packages, you will see a clear message.

Example output:

❯ LOCAL_PRIMER=1 script/server
 Development Primer is linked to the local Primer repository found here
14:09:14 web.1        | started with pid 36981
14:09:14 assets.1     | started with pid 36982
14:09:14 longpoll.1   | started with pid 36984
14:09:14 git-daemon.1 | started with pid 36986
14:09:14 gitauth.1    | started with pid 36988
14:09:14 codeload.1   | started with pid 36991
14:09:14 babeld.1     | started with pid 36996

Resetting github/github development assets

To turn off Primerize, rerun script/server without the LOCAL_PRIMER flag. The script checks if you are still linked and restores everything to normal.

Example output:

❯ script/server
 Development Primer is linked to the local Primer repository found here
Turning off linked primer
extracting primer-alerts@1.5.5.tgz
extracting primer-avatars@1.5.2.tgz
extracting primer-base@1.7.0.tgz
extracting primer-blankslate@1.4.5.tgz
extracting primer-box@2.5.5.tgz
extracting primer-branch-name@1.0.3.tgz
extracting primer-breadcrumb@1.5.1.tgz
extracting primer-buttons@2.5.3.tgz
extracting primer-core@6.8.0.tgz
extracting primer-forms@2.1.0.tgz
extracting primer-labels@1.5.5.tgz
extracting primer-layout@1.4.5.tgz
extracting primer-markdown@3.7.5.tgz
extracting primer-marketing-buttons@1.0.4.tgz
extracting primer-marketing-support@1.5.0.tgz
extracting primer-marketing-type@1.4.5.tgz
extracting primer-marketing-utilities@1.6.1.tgz
extracting primer-marketing@6.2.0.tgz
extracting primer-navigation@1.5.3.tgz
extracting primer-page-headers@1.4.5.tgz
extracting primer-page-sections@1.4.5.tgz
extracting primer-popover@0.0.6.tgz
extracting primer-product@5.6.2.tgz
extracting primer-subhead@1.0.3.tgz
extracting primer-support@4.5.2.tgz
extracting primer-table-object@1.4.5.tgz
extracting primer-tables@1.4.5.tgz
extracting primer-tooltips@1.5.3.tgz
extracting primer-truncate@1.4.5.tgz
extracting primer-utilities@4.8.5.tgz
extracting primer@10.4.0.tgz
regenerating node binstubs
14:13:17 web.1        | started with pid 38585
14:13:17 assets.1     | started with pid 38586
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