Developer Documentation Plugins
WordPress is fast, lightweight, and easy to use.Which means it is easy to sort out your developer documentation plugins. To ensure it stays that way, the Core Team thinks carefully about adding functionality to the core WordPress code. Still, users often find the need to graft additional functionality onto WordPress to meet their needs. This section of the Codex offers guidelines and references for anyone wishing to modify, extend, or contribute to WordPress.
You may also wish to consult the Developer Documentation FAQ.
WARNING: Programming Code Ahead
The following articles may use programming terms without offering detailed explanations for non-programmers.
Although the alteration of the downloadable files for WordPress is limited to a few distinct programmers, every WordPress user has the ability to effect change in the core WordPress code, making WordPress highly customizable.
Writing a Plugin – The best starting place for learning about how to develop plugins
WordPress Coding Standards – General information about coding standards for WordPress development
Debugging in WordPress – Reference and guide for using the built-in debugging system in WordPress.
Data Validation – A must-read for WordPress plugin authors. Describes the functions used by WordPress to validate and sanitize data. Plugin authors should be familiar with these functions and ideas.
Plugin Submission and Promotion – Once you have written your plugin, here are some hints on distributing it widely
Migrating Plugins and Themes – Contains information on how to upgrade your Plugin so it will work from version to version of WordPress
Function Reference – Complete PHP function reference for WordPress (version 2.1, with links to previous versions)
Global Variables – A list of all global variables created by WordPress
Plugin Resources – Comprehensive list of other references for plugin development
Post Types – Creating new types of posts other than the posts that display on the main loop.
Taxonomies – Creating new types of taxonomies other than the built-in ones.
Reserved Terms – A list of reserved terms in WordPress.
Plugin API – Hooks, Actions, and Filters to use in your Plugins (version 2.1; has links to older version articles)
Shortcode API – A tutorial and reference for the shortcode API (new in version 2.5)
Dashboard Widgets API – A reference with examples for adding new widgets to the admin dashboard.
Settings API – A reference with examples for adding new settings to existing settings screens.
Options API – Details about the generic option storage system.
Transients API – Details about the temporary/time-constrained data storage system.
Widgets API – A reference with examples for creating widgets for use in sidebars.
Quicktags API – A reference for adding buttons to the HTML editor.
Rewrite API – Details about the URL rewriting API.
Theme Customization API – Details about the API for Theme Customization screen.
Filesystem API – Reference for reading and writing local files to the filesystem to be done securely, on a variety of host types.