WordPress Developer Resources
developer.wordpress.org is the official home of WordPress developer documentation: the Theme and Plugin handbooks, the Block Editor handbook, the Code Reference for every function, hook and class, the REST API and WP-CLI docs, coding standards and the Advanced Administration handbook with security hardening. It is the reference to keep open while building anything custom. The handbooks are written and maintained by the open source project.
Guide
Web Development
WordPress.org
Reference
Intermediate
Free
What you will find here
developer.wordpress.org gathers every official WordPress developer handbook in one place. The ones that matter most for building client sites:
- Theme Handbook: how themes are structured, the template hierarchy, block themes and
theme.json, classic themes and child themes. - Plugin Handbook: plugin headers, activation and uninstall, hooks (actions and filters), security (nonces, sanitising input, escaping output, capabilities), settings pages and custom post types.
- Block Editor Handbook: building custom blocks and extending the editor (covered in its own library entry).
- Code Reference: a page for every function, hook, class and method in core, with the source code, parameters, and user-contributed notes and examples.
- Common APIs, REST API and WP-CLI: options, transients, HTTP requests, the JSON API for headless work, and command-line management of sites.
- Advanced Administration: server setup, performance, backups, upgrading, multisite and a security hardening guide covering file permissions, keeping software updated, and protecting the admin area.
- Coding Standards: the PHP, JavaScript, CSS, HTML and accessibility standards WordPress itself follows.
- WordPress Playground: run WordPress in your browser to test code without installing anything.
Is it worth your time?
Yes, if you write any code for WordPress. Most bad WordPress code on the internet comes from copied snippets that skip escaping, use the wrong hook or break on updates. The handbooks show the supported way, and the Code Reference tells you exactly what a function returns and which version added it.
How to use it well
Do not read it cover to cover. Start with the Plugin Handbook's basics and security chapters and the Theme Handbook's sections on block themes and child themes. After that, use search: when a tutorial calls a function, look it up in the Code Reference before you trust it. The security hardening page in Advanced Administration is worth reading once in full before you launch your first client site.
Prerequisites
Comfortable HTML and CSS, and basic PHP: variables, arrays, functions and if statements. For the Block Editor Handbook you also need modern JavaScript and Node.js tooling.
Free or paid
Free and openly licensed. No account needed.
What you can do after
Write a small plugin that follows WordPress conventions, build or adapt a theme safely, and read other people's plugin code well enough to judge whether it is safe to install on a client site.
Common questions
Is this the same as the WordPress.org support docs? No. End-user help lives in the WordPress.org documentation for site owners; this site is for developers and administrators.
Is the Code Reference current? It is generated from the core source, so it matches the latest release, and each entry notes the version where a function appeared or changed.
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