WordPress allows customization of directory locations and URLs through constants. These are useful for non-standard installations, security, or organizational preferences.

Site URL Constants

WP_SITEURL

define( 'WP_SITEURL', 'https://example.com' );

• Type: String (URL)
• Default: Retrieved from siteurl option in database
• Purpose: The URL where WordPress core files reside
• Effect: Overrides database siteurl value
• Must Include: Protocol (https:// or http://)
• Must NOT Include: Trailing slash

WP_HOME

define( 'WP_HOME', 'https://example.com' );

• Type: String (URL)
• Default: Retrieved from home option in database
• Purpose: The URL users type to reach your site
• Effect: Overrides database home value
• Must Include: Protocol
• Must NOT Include: Trailing slash

WordPress in Subdirectory

// WordPress in /blog/ folder, but site accessed at root
define( 'WP_HOME', 'https://example.com' );
define( 'WP_SITEURL', 'https://example.com/blog' );

Benefits of Hardcoding

1. Performance: Skips database lookup
2. Security: Prevents redirect attacks via database modification
3. Reliability: Works even if database is corrupted

Content Directory

WP_CONTENT_DIR

define( 'WP_CONTENT_DIR', dirname( __FILE__ ) . '/custom-content' );

• Type: String (absolute path)
• Default: {ABSPATH}/wp-content
• Purpose: Absolute filesystem path to wp-content directory
• Must Be: Full server path (not URL)
• Must NOT Have: Trailing slash

WP_CONTENT_URL

define( 'WP_CONTENT_URL', 'https://example.com/custom-content' );

• Type: String (URL)
• Default: {site_url}/wp-content
• Purpose: URL to wp-content directory
• Must NOT Have: Trailing slash

Renaming wp-content Example

// Move and rename wp-content to "assets"
define( 'WP_CONTENT_DIR', '/var/www/html/assets' );
define( 'WP_CONTENT_URL', 'https://example.com/assets' );

Plugin Directory

WP_PLUGIN_DIR

define( 'WP_PLUGIN_DIR', WP_CONTENT_DIR . '/extensions' );

• Type: String (absolute path)
• Default: {WP_CONTENT_DIR}/plugins
• Purpose: Filesystem path to plugins directory

WP_PLUGIN_URL

define( 'WP_PLUGIN_URL', WP_CONTENT_URL . '/extensions' );

• Type: String (URL)
• Default: {WP_CONTENT_URL}/plugins
• Purpose: URL to plugins directory

PLUGINDIR (Relative)

define( 'PLUGINDIR', 'wp-content/extensions' );

• Type: String (relative path)
• Default: wp-content/plugins
• Purpose: Relative path to plugins from WordPress root

Custom Plugin Directory Example

// Plugins in /extensions/ instead of /wp-content/plugins/
define( 'WP_PLUGIN_DIR', dirname( __FILE__ ) . '/extensions' );
define( 'WP_PLUGIN_URL', 'https://example.com/extensions' );
define( 'PLUGINDIR', 'extensions' );

Must-Use Plugins Directory

WPMU_PLUGIN_DIR

define( 'WPMU_PLUGIN_DIR', WP_CONTENT_DIR . '/mu-extensions' );

• Type: String (absolute path)
• Default: {WP_CONTENT_DIR}/mu-plugins
• Purpose: Directory for must-use plugins (auto-loaded)

WPMU_PLUGIN_URL

define( 'WPMU_PLUGIN_URL', WP_CONTENT_URL . '/mu-extensions' );

• Type: String (URL)
• Default: {WP_CONTENT_URL}/mu-plugins
• Purpose: URL to must-use plugins directory

Uploads Directory

UPLOADS

define( 'UPLOADS', 'wp-content/media' );

• Type: String (relative path)
• Default: wp-content/uploads
• Purpose: Relative path (from ABSPATH) to uploads directory
• Note: This is relative, NOT absolute

Important Notes

1. Cannot use absolute paths
2. Path is relative to ABSPATH, not WP_CONTENT_DIR
3. WordPress still creates year/month subfolders by default

Move Uploads Outside wp-content

// Uploads at site.com/media/ instead of site.com/wp-content/uploads/
define( 'UPLOADS', 'media' );

Uploads with Custom wp-content

When using custom WP_CONTENT_DIR, uploads path needs adjustment:

define( 'WP_CONTENT_DIR', '/var/www/html/assets' );
define( 'WP_CONTENT_URL', 'https://example.com/assets' );
define( 'UPLOADS', 'assets/media' ); // Relative to ABSPATH

Theme Directory

WordPress doesn’t have direct constants for theme directory, but themes reside in:
{WP_CONTENT_DIR}/themes/

To customize, use WP_CONTENT_DIR and include themes within it.

register_theme_directory()

For additional theme directories (not via wp-config.php):

// In a plugin or theme
register_theme_directory( '/var/www/shared-themes' );

Languages Directory

WP_LANG_DIR

define( 'WP_LANG_DIR', dirname( __FILE__ ) . '/languages' );

• Type: String (absolute path)
• Default: {WP_CONTENT_DIR}/languages
• Purpose: Directory for WordPress translation files (.mo, .po)

LANGDIR (Deprecated)

define( 'LANGDIR', 'my-languages' ); // Deprecated

• Status: Deprecated
• Replacement: Use WP_LANG_DIR

Temporary Directory

WP_TEMP_DIR

define( 'WP_TEMP_DIR', '/tmp/wordpress' );

• Type: String (absolute path)
• Default: System temp directory
• Purpose: Directory for temporary files during updates, uploads, etc.
• Requirements: Must be writable by web server

WordPress Core Directory

ABSPATH

if ( ! defined( 'ABSPATH' ) ) {
    define( 'ABSPATH', __DIR__ . '/' );
}

• Type: String (absolute path)
• Default: Directory containing wp-config.php
• Purpose: Absolute path to WordPress installation
• Must Have: Trailing slash
• Note: Defined at end of wp-config.php, do not redefine

Complete Custom Directory Structure

Example: Security-Focused Layout

/var/www/
├── config/
│   └── wp-config.php      # Outside web root
├── html/                   # Document root
│   ├── index.php          # Modified to find wp-config.php
│   ├── wp/                # WordPress core
│   ├── assets/            # Custom wp-content
│   │   ├── themes/
│   │   ├── extensions/    # Plugins
│   │   ├── mu-extensions/ # MU plugins
│   │   └── media/         # Uploads
│   └── languages/
└── logs/
    └── debug.log

wp-config.php:

<?php
// Site URLs
define( 'WP_HOME', 'https://example.com' );
define( 'WP_SITEURL', 'https://example.com/wp' );

// Content directory
define( 'WP_CONTENT_DIR', '/var/www/html/assets' );
define( 'WP_CONTENT_URL', 'https://example.com/assets' );

// Plugins
define( 'WP_PLUGIN_DIR', WP_CONTENT_DIR . '/extensions' );
define( 'WP_PLUGIN_URL', WP_CONTENT_URL . '/extensions' );
define( 'PLUGINDIR', 'assets/extensions' );

// MU Plugins
define( 'WPMU_PLUGIN_DIR', WP_CONTENT_DIR . '/mu-extensions' );
define( 'WPMU_PLUGIN_URL', WP_CONTENT_URL . '/mu-extensions' );

// Uploads (relative to ABSPATH which is /var/www/html/wp/)
define( 'UPLOADS', '../assets/media' );

// Languages
define( 'WP_LANG_DIR', '/var/www/html/languages' );

// Debug log outside web root
define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', '/var/www/logs/debug.log' );
define( 'WP_DEBUG_DISPLAY', false );

// ABSPATH
if ( ! defined( 'ABSPATH' ) ) {
    define( 'ABSPATH', '/var/www/html/wp/' );
}

require_once ABSPATH . 'wp-settings.php';

html/index.php (modified):

<?php
define( 'WP_USE_THEMES', true );
require __DIR__ . '/wp/wp-blog-header.php';

Symlink Handling

Theme/Plugin Symlinks

For development with symlinked themes/plugins:

// In wp-config.php - resolve symlinks for proper paths
$_SERVER['SCRIPT_FILENAME'] = realpath( $_SERVER['SCRIPT_FILENAME'] );

CDN URL Configuration

For serving content from a CDN:

define( 'WP_CONTENT_URL', 'https://cdn.example.com/wp-content' );

Note: This only affects content_url() and related functions. Many plugins have their own CDN settings.

Path Constants Quick Reference

Best Practices

1. Always use trailing-slash consistently: ABSPATH has it, others don’t
2. Use constants for building paths: WP_CONTENT_DIR . '/custom' not hardcoded paths
3. Test after changes: Path misconfiguration breaks sites completely
4. Use absolute paths for filesystem, URLs for web access
5. Keep sensitive files outside web root: wp-config.php, logs, etc.