What Is the WordPress Codex?

The WordPress Codex held documentation for both WordPress users and developers, from setting up a first site to core development. It was organized into categories such as ‘Learn How to Use WordPress,’ ‘Working with Themes,’ and ‘Write a Plugin,’ alongside a glossary of terms, step-by-step tutorials, and troubleshooting tips.

It was also a community wiki, and it pointed readers toward ways to volunteer on the wider WordPress project.

Where Codex content lives now

The Codex is no longer actively maintained. The WordPress documentation team moved its content to two current homes, and the Make WordPress Documentation handbook archives that migration as complete.

End-user articles went to HelpHub, now published at wordpress.org/documentation: 105 pages in the first phase, 351 version pages, and 54 more in a second phase. The function and hook reference moved to the Code Reference on developer.wordpress.org, and the last of that reference content followed between December 2019 and February 2021. Migrated Codex pages carry a notice pointing you to the new location.

Which WordPress docs to use

Start with the two current sites, and treat the Codex as an archive:

• To learn how to use WordPress (installing it, publishing content, customizing your site), go to WordPress Documentation, also called HelpHub.
• To look up code (functions, hooks, classes, the REST API, and the plugin and theme handbooks), go to developer.wordpress.org, also called DevHub.
• If an old link or search result lands you on the Codex, cross-check anything code-related against the Code Reference, because Codex examples predate the migration.

If you're learning WordPress from the ground up rather than looking up a single answer, our list of 25 resources to learn WordPress is a good next stop.