wppaste
WordPress

rest_url( string $path = '', string $scheme = 'rest' ): string

Since
4.4.0
Source
wp-includes/rest-api.php:599

Builds a full REST API URL by combining a route with the site's REST base and passed through get_rest_url(). The returned string is not escaped, so wrap it in esc_url() or esc_url_raw() before printing or storing it. On multisite, it always targets the current site because it calls get_rest_url() with a null site ID; use get_rest_url() directly when you need a different site's REST URL.

Retrieves the URL to a REST endpoint.

Description

Note: The returned URL is NOT escaped.

Compatibility

WordPress
since 4.4.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$pathstringoptional
REST route. Default empty.Default: ''
$schemestringoptional
Sanitization scheme. Default 'rest'.Default: 'rest'

Return value

string
Full URL to the endpoint.

Code examples

Every example is editable and runs in a real WordPress booted in your browser by WordPress Playground. Press Run, then edit the code: clicking away re-runs it. Nothing is sent anywhere until you do.

Get the REST API URL for a specific post

Build a link to the wp/v2/posts endpoint for one of the baseline posts.

$post_id = 2;
$endpoint = sprintf( 'wp/v2/posts/%d', $post_id );

echo esc_html( rest_url( $endpoint ) );

rest_url() does not escape its return value, so esc_html() or esc_url() is added here before printing.

Pass the REST root URL to a script for client-side API requests

Register the core wp-api-request script and localize it with the REST root so front-end JavaScript can call the API.

add_action( 'wp_enqueue_scripts', function() {
	wp_enqueue_script( 'wp-api-request' );
	wp_localize_script( 'wp-api-request', 'wpApiSettings', array(
		'root'  => esc_url_raw( rest_url() ),
		'nonce' => wp_create_nonce( 'wp_rest' ),
	) );
} );

add_action( 'wp_footer', function() {
	printf( '<p>REST root: %s</p>', esc_html( rest_url() ) );
} );

esc_url_raw() is used here because the value is being written into a JavaScript settings object rather than printed as HTML.

Common problems and fixes · 3

Why do I have to escape the output of rest_url()?

The docblock states plainly that the returned URL is NOT escaped, and the function just forwards to get_rest_url() without any sanitization step. Printing it raw into HTML is unsafe. - Use esc_url() when echoing it inside markup. - Use esc_url_raw() when storing it or passing it into JavaScript or an HTTP request.

Why does rest_url() return the wrong site's URL on a multisite network?

rest_url() always calls get_rest_url( null, $path, $scheme ), and passing null tells get_rest_url() to use the current site rather than any specific blog. If you're building a URL for a different site in the network, this function cannot target it. - Call get_rest_url( $blog_id, $path, $scheme ) directly instead.

What does the $scheme argument in rest_url() actually control?

It's a sanitization scheme string (default 'rest'), not a network protocol like 'https'. Passing 'https' as $scheme will not force the returned URL onto HTTPS; it only changes how the URL is filtered internally by get_rest_url(). - Leave $scheme at its default unless you specifically need a different sanitization context.

Alternatives and related functions

get_rest_url
When you need a REST URL for a specific multisite blog ID rather than the current site.
home_url
When you need the site's front-end home URL instead of a REST API endpoint.
admin_url
When the link should point to a wp-admin page rather than the REST API.
rest_get_route_for_post
When you only need the REST route for a post object to build a link, without assembling the full URL yourself.

Performance profile

How much work a call to rest_url() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Moderate

Reads stored settings via get_option(), cached per request but not free on a cold cache.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
8

Executed per call on PHP 8.5. The body compiles to 8.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
50

50 places in core call this, so the cost is paid more often than your own code shows.

What it touches

  • optionoption read or writeget_option()one call below rest_url()
  • hookthird-party callbacksapply_filters()one call below rest_url()

Further down the call graph this can also reach cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost rest_url() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
always8get_rest_url()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 8 instructions, 8 executed per call, 0 branches. The work does not change between versions.

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 1

Used by · 50

Show all 50

Source code

View on Trac View on GitHub 

function rest_url( $path = '', $scheme = 'rest' ) {	return get_rest_url( null, $path, $scheme );}

Changelog

Introduced in 4.4.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/rest-api.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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