WordPress Links & URL API Overview

Last updated: February 12, 2026

WordPress provides a comprehensive URL generation system that handles permalinks, site URLs, admin URLs, and canonical URL management. The system is flexible, supporting both "pretty permalinks" and query-string-based URLs.

Core Concepts

URL Types

WordPress distinguishes between several URL types:

URL Type	Function	Purpose
Home URL	`home_url()`	Front-end site address (where visitors see content)
Site URL	`site_url()`	WordPress installation address (where files live)
Admin URL	`admin_url()`	WordPress admin dashboard
Content URL	`content_url()`	wp-content directory
Plugins URL	`plugins_url()`	Plugins directory
Includes URL	`includes_url()`	wp-includes directory

Permalink Structure

Permalinks are the permanent URLs to posts, pages, and archives. WordPress supports:

Plain: ?p=123
Day and name: /2024/02/09/sample-post/
Month and name: /2024/02/sample-post/
Numeric: /archives/123
Post name: /sample-post/
Custom structure: Using rewrite tags like %postname%, %category%, %author%

URL Scheme Handling

The set_url_scheme() function normalizes URLs to use the correct protocol:

// Forces HTTPS
set_url_scheme( $url, 'https' );

// Uses current scheme (respects is_ssl())
set_url_scheme( $url );

// Relative URL (strips protocol and host)
set_url_scheme( $url, 'relative' );

Primary Source Files

File	Purpose
`link-template.php`	Main URL generation functions (4900+ lines)
`canonical.php`	Canonical URL redirect handling
`bookmark.php`	Legacy links/blogroll management

URL Generation Architecture

Post Permalinks

get_permalink( $post )
    ├── get_page_link()      → For pages
    ├── get_attachment_link() → For attachments  
    └── get_post_permalink() → For custom post types

Archive Permalinks

Archive URLs
    ├── get_year_link()          → /2024/
    ├── get_month_link()         → /2024/02/
    ├── get_day_link()           → /2024/02/09/
    ├── get_term_link()          → /category/news/
    ├── get_author_posts_url()   → /author/admin/
    └── get_post_type_archive_link() → /books/

Feed URLs

Feed URLs
    ├── get_feed_link()               → Main site feed
    ├── get_post_comments_feed_link() → Post comments feed
    ├── get_author_feed_link()        → Author posts feed
    ├── get_category_feed_link()      → Category feed
    └── get_tag_feed_link()           → Tag feed

Canonical URLs

Canonical URLs prevent duplicate content issues by redirecting to the "correct" URL version:

How `redirect_canonical()` Works

Builds requested URL from $_SERVER variables
Determines correct URL based on query type (single, archive, etc.)
Handles edge cases:
- www vs non-www normalization
- Trailing slash consistency
- Query parameter cleanup
- Pagination handling
Issues 301 redirect if URLs differ

SEO Implications

Consolidates link equity to canonical URL
Prevents penalty for duplicate content
Normalizes URL variations

Legacy Bookmarks (Links Manager)

The Bookmarks API manages external links (formerly "blogroll"). Disabled by default since WordPress 3.5 but still functional.

Link Data Structure

object(stdClass) {
    link_id          // Unique ID
    link_url         // The URL
    link_name        // Display name
    link_image       // Optional image URL
    link_target      // _blank, _top, or empty
    link_description // Description text
    link_visible     // Y or N
    link_owner       // User ID who created
    link_rating      // 0-10 rating
    link_updated     // Last update timestamp
    link_rel         // Relationship (XFN)
    link_notes       // Private notes
    link_rss         // RSS feed URL
    link_category    // Array of category IDs
}

Trailing Slashes

WordPress handles trailing slashes via user_trailingslashit():

// Adds or removes trailing slash based on permalink settings
$url = user_trailingslashit( $url, 'single' );

The $type_of_url parameter allows different handling for:

single – Single posts
page – Pages
category – Category archives
home – Home page
feed – Feeds
paged – Paginated archives

Multisite URL Functions

For multisite installations:

Function	Purpose
`network_home_url()`	Network home URL
`network_site_url()`	Network site URL
`network_admin_url()`	Network admin URL
`get_home_url( $blog_id )`	Specific site home URL
`get_admin_url( $blog_id )`	Specific site admin URL

Shortlinks

WordPress provides a shortlink system for sharing:

// Get shortlink for current post
$shortlink = wp_get_shortlink();

// Default format: ?p=123
// Can be filtered for custom shorteners

The shortlink is:

Added to <head> via wp_shortlink_wp_head()
Sent as HTTP header via wp_shortlink_header()

Common Patterns

Getting the Current Page URL

// For posts/pages
$url = get_permalink();

// For archives
$url = get_term_link( $term );

// For search results
$url = get_search_link( $query );

Building Admin URLs

// Edit post screen
$url = get_edit_post_link( $post_id );

// Custom admin page
$url = admin_url( 'admin.php?page=my-plugin' );

// User profile
$url = get_edit_user_link( $user_id );

Navigation Links

// Previous/Next post
$prev = get_previous_post_link();
$next = get_next_post_link();

// Pagination
$links = paginate_links( $args );

Best Practices

Use URL functions instead of hardcoding paths
Escape URLs with esc_url() before output
Respect permalink structure – use built-in functions
Use relative URLs when appropriate for portability
Filter URLs only when necessary; prefer built-in hooks