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The Mozilla Developer Network uses a WYSIWYG editor called CKEditor. CKEditor is an open source utility which brings the power of rich text editing to the web. This document details how to update CKEditor within the MDN codebase.

Building CKEditor

To rebuild CKEditor, run this on the host system:

cd kuma/static/js/libs/ckeditor/
./  # Creates a Java container, builds CKEditor
docker-compose exec web make build-static

This builds CKEditor within a Docker VM, using the Java ckbuilder tool from CKSource, then builds static resources so that the updated editor is installed where it belongs.

To rebuild CKEditor locally, if you have Java installed:

cd kuma/static/js/libs/ckeditor/source/
docker-compose exec web make build-static

Portions of the build process will take a few minutes so don’t expect an immediate result.

Updating CKEditor

To update the CKEditor version, you’ll need to edit and change the value of CKEDITOR_VERSION. Updating is important to keep MDN in sync with CKEditor’s functional and security updates.

Updating CKEditor plugins

Some plugins are maintained by MDN staff in the Kuma repo. Others are updated to the tag or commit number specified in

Change to CKEditor plugins which are bundled into Kuma should be made in the directory /kuma/static/js/libs/ckeditor/source/ckeditor/plugins/.

Once you’ve made changes to a plugin, be sure to build the editor and the static resources again, as described in Building CKEditor.