WP_REST_Server

Last updated: February 12, 2026

Core class implementing the WordPress REST API server. Handles route registration, request dispatch, and response formatting.

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

Constants

Constant	Value	Description
`READABLE`	`'GET'`	GET transport method
`CREATABLE`	`'POST'`	POST transport method
`EDITABLE`	`'POST, PUT, PATCH'`	Writable methods
`DELETABLE`	`'DELETE'`	DELETE transport method
`ALLMETHODS`	`'GET, POST, PUT, PATCH, DELETE'`	All methods

Properties

Property	Type	Visibility	Description
`$namespaces`	array	protected	Namespaces registered to server
`$endpoints`	array	protected	Endpoints registered to server
`$route_options`	array	protected	Options for routes
`$embed_cache`	array	protected	Cache for embedded requests
`$dispatching_requests`	array	protected	Request stack being handled

Methods

__construct()

Instantiates the REST server with default routes.

public function __construct()

Registers default / (index) and /batch/v1 endpoints.

check_authentication()

Checks authentication headers.

public function check_authentication(): WP_Error|null|true

Returns:

WP_Error if authentication error
null if no authentication method used
true if authentication succeeded

Triggers rest_authentication_errors filter.

serve_request()

Handles serving a REST API request.

public function serve_request( string $path = null ): null|false

Parameter	Type	Description
`$path`	string\|null	Request route. Default uses `$_SERVER['PATH_INFO']`

Returns: null if served (or HEAD request), false on error.

Flow:

Sets up request from $_SERVER, $_GET, $_POST, $_FILES
Handles method override via _method param or X-HTTP-Method-Override header
Calls check_authentication()
Dispatches request
Applies rest_post_dispatch filter
Handles envelope (_envelope param)
Sends headers and JSON response

response_to_data()

Converts a response to data for sending.

public function response_to_data( WP_REST_Response $response, bool|string[] $embed ): array

Parameter	Type	Description
`$response`	WP_REST_Response	Response object
`$embed`	bool\|string[]	Whether to embed links

Returns: Array with _links and optionally _embedded.

get_response_links() (static)

Extracts links from a response.

public static function get_response_links( WP_REST_Response $response ): array

Parameter	Type	Description
`$response`	WP_REST_Response	Response object

Returns: Map of link relation to list of link hashes.

get_compact_response_links() (static)

Gets links with CURIE-shortened relations.

public static function get_compact_response_links( WP_REST_Response $response ): array

Parameter	Type	Description
`$response`	WP_REST_Response	Response object

Returns: Links with wp: prefixes for WordPress relations.

envelope_response()

Wraps response in an envelope.

public function envelope_response( WP_REST_Response $response, bool|string[] $embed ): WP_REST_Response

Parameter	Type	Description
`$response`	WP_REST_Response	Response to wrap
`$embed`	bool\|string[]	Embed setting

Returns: Response with body, status, and headers data.

register_route()

Registers a route to the server.

public function register_route( string $route_namespace, string $route, array $route_args, bool $override = false ): void

Parameter	Type	Description
`$route_namespace`	string	Namespace
`$route`	string	Route path
`$route_args`	array	Route arguments
`$override`	bool	Override existing route

Note: Use register_rest_route() wrapper function instead.

get_routes()

Retrieves the route map.

public function get_routes( string $route_namespace = '' ): array

Parameter	Type	Description
`$route_namespace`	string	Filter to specific namespace

Returns: Map of route regex to handlers.

get_namespaces()

Retrieves registered namespaces.

public function get_namespaces(): string[]

Returns: Array of namespace strings.

get_route_options()

Retrieves options for a route.

public function get_route_options( string $route ): array|null

Parameter	Type	Description
`$route`	string	Route pattern

Returns: Route options or null if not found.

dispatch()

Matches request to handler and calls it.

public function dispatch( WP_REST_Request $request ): WP_REST_Response

Parameter	Type	Description
`$request`	WP_REST_Request	Request to dispatch

Returns: Response from the matched callback.

Flow:

Applies rest_pre_dispatch filter
Matches request to route
Validates and sanitizes parameters
Calls respond_to_request()

is_dispatching()

Checks if server is currently handling a request.

public function is_dispatching(): bool

Returns: true during dispatch, false otherwise.

Since: 6.5.0

match_request_to_handler() (protected)

Matches a request to its handler.

protected function match_request_to_handler( WP_REST_Request $request ): array|WP_Error

Parameter	Type	Description
`$request`	WP_REST_Request	Request object

Returns: array( $route, $handler ) or WP_Error.

Error Codes:

rest_no_route — No matching route found (404)

respond_to_request() (protected)

Dispatches request to the callback handler.

protected function respond_to_request( WP_REST_Request $request, string $route, array $handler, WP_Error|null $response ): WP_REST_Response

Parameter	Type	Description
`$request`	WP_REST_Request	Request object
`$route`	string	Matched route regex
`$handler`	array	Matched handler
`$response`	WP_Error\|null	Pre-existing error

Returns: Response from callback.

Flow:

rest_request_before_callbacks filter
Calls permission_callback
rest_dispatch_request filter
Calls callback
rest_request_after_callbacks filter

get_index()

Retrieves the site index (root endpoint).

public function get_index( WP_REST_Request $request ): WP_REST_Response

Parameter	Type	Description
`$request`	WP_REST_Request	Request object

Returns: Response with site info, namespaces, routes, authentication.

get_namespace_index()

Retrieves index for a namespace.

public function get_namespace_index( WP_REST_Request $request ): WP_REST_Response|WP_Error

Parameter	Type	Description
`$request`	WP_REST_Request	Request with `namespace` param

Returns: Response with namespace routes or error if not found.

get_data_for_routes()

Retrieves publicly-visible data for routes.

public function get_data_for_routes( array $routes, string $context = 'view' ): array[]

Parameter	Type	Description
`$routes`	array	Routes to describe
`$context`	string	`view` or `help`

Returns: Route data keyed by route.

get_data_for_route()

Retrieves publicly-visible data for a single route.

public function get_data_for_route( string $route, array $callbacks, string $context = 'view' ): array|null

Parameter	Type	Description
`$route`	string	Route pattern
`$callbacks`	array	Route callbacks
`$context`	string	Data context

Returns: Route data or null if hidden.

serve_batch_request_v1()

Serves batch API requests.

public function serve_batch_request_v1( WP_REST_Request $batch_request ): WP_REST_Response

Parameter	Type	Description
`$batch_request`	WP_REST_Request	Batch request with `requests` array

Returns: Response with responses array (207 Multi-Status).

Request Format:

{
    "validation": "normal",
    "requests": [
        { "path": "/wp/v2/posts/1", "method": "PUT", "body": {}, "headers": {} }
    ]
}

Validation Modes:

normal — Execute all, return individual results
require-all-validate — Abort if any request fails validation

send_header()

Sends an HTTP header.

public function send_header( string $key, string $value ): void

Parameter	Type	Description
`$key`	string	Header name
`$value`	string	Header value

send_headers()

Sends multiple HTTP headers.

public function send_headers( array $headers ): void

Parameter	Type	Description
`$headers`	array	Map of header name to value

remove_header()

Removes an HTTP header.

public function remove_header( string $key ): void

Parameter	Type	Description
`$key`	string	Header name

Since: 4.8.0

get_raw_data() (static)

Retrieves raw request body.

public static function get_raw_data(): string

Returns: Raw php://input contents.

get_headers()

Extracts headers from $_SERVER array.

public function get_headers( array $server ): array

Parameter	Type	Description
`$server`	array	Server variables

Returns: Extracted headers.

Handles:

HTTP_* prefixed headers
CONTENT_TYPE, CONTENT_LENGTH, CONTENT_MD5
REDIRECT_HTTP_AUTHORIZATION fallback

Protected Methods

error_to_response()

Converts WP_Error to response object.

protected function error_to_response( WP_Error $error ): WP_REST_Response

json_error()

Gets JSON error representation.

protected function json_error( string $code, string $message, int|null $status = null ): string

get_json_encode_options()

Gets JSON encoding options.

protected function get_json_encode_options( WP_REST_Request $request ): int

Respects _pretty param for pretty printing.

embed_links()

Embeds links into response data.

protected function embed_links( array $data, bool|string[] $embed = true ): array

get_json_last_error()

Gets last JSON encoding error message.

protected function get_json_last_error(): false|string

set_status()

Sends HTTP status code.

protected function set_status( int $code ): void

get_max_batch_size()

Gets maximum batch request size.

protected function get_max_batch_size(): int

Returns: Default 25, filterable via rest_get_max_batch_size.

add_active_theme_link_to_index()

Adds active theme link to index response.

protected function add_active_theme_link_to_index( WP_REST_Response $response ): void

Since: 5.7.0

add_site_logo_to_index()

Adds site logo to index response.

protected function add_site_logo_to_index( WP_REST_Response $response ): void

Since: 5.8.0

add_site_icon_to_index()

Adds site icon to index response.

protected function add_site_icon_to_index( WP_REST_Response $response ): void

Since: 5.9.0

add_image_to_index()

Adds image data to index response.

protected function add_image_to_index( WP_REST_Response $response, int $image_id, string $type ): void

Since: 5.9.0

get_target_hints_for_link() (static)

Gets target hints for a link.

protected static function get_target_hints_for_link( array $link ): array|null

Since: 6.7.0

WP_REST_Server

Constants

Properties

Methods

__construct()

check_authentication()

serve_request()

response_to_data()

get_response_links() (static)

get_compact_response_links() (static)

envelope_response()

register_route()

get_routes()

get_namespaces()

get_route_options()

dispatch()

is_dispatching()

match_request_to_handler() (protected)

respond_to_request() (protected)

get_index()

get_namespace_index()

get_data_for_routes()

get_data_for_route()

serve_batch_request_v1()

send_header()

send_headers()

remove_header()

get_raw_data() (static)

get_headers()

Protected Methods

error_to_response()

json_error()

get_json_encode_options()

embed_links()

get_json_last_error()

set_status()

get_max_batch_size()

add_active_theme_link_to_index()

add_site_logo_to_index()

add_site_icon_to_index()

add_image_to_index()

get_target_hints_for_link() (static)

More in Rest Api

WP_REST_Request

WP_REST_Response

REST API Functions