diff --git a/wp-includes/rest-api.php b/wp-includes/rest-api.php
index 37d55f7ccf..2c0e8f7e18 100644
--- a/wp-includes/rest-api.php
+++ b/wp-includes/rest-api.php
@@ -230,6 +230,20 @@ function create_initial_rest_routes() {
 	$controller = new WP_REST_Comments_Controller;
 	$controller->register_routes();
 
+	/**
+	 * Filters the search handlers to use in the REST search controller.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param array $search_handlers List of search handlers to use in the controller. Each search
+	 *                               handler instance must extend the `WP_REST_Search_Handler` class.
+	 *                               Default is only a handler for posts.
+	 */
+	$search_handlers = apply_filters( 'wp_rest_search_handlers', array( new WP_REST_Post_Search_Handler() ) );
+
+	$controller = new WP_REST_Search_Controller( $search_handlers );
+	$controller->register_routes();
+
 	// Settings.
 	$controller = new WP_REST_Settings_Controller;
 	$controller->register_routes();
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-search-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-search-controller.php
new file mode 100644
index 0000000000..8aaf9c6476
--- /dev/null
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-search-controller.php
@@ -0,0 +1,359 @@
+<?php
+/**
+ * REST API: WP_REST_Search_Controller class
+ *
+ * @package WordPress
+ * @subpackage REST_API
+ * @since 5.0.0
+ */
+
+/**
+ * Core class to search through all WordPress content via the REST API.
+ *
+ * @since 5.0.0
+ *
+ * @see WP_REST_Controller
+ */
+class WP_REST_Search_Controller extends WP_REST_Controller {
+
+	/**
+	 * ID property name.
+	 */
+	const PROP_ID = 'id';
+
+	/**
+	 * Title property name.
+	 */
+	const PROP_TITLE = 'title';
+
+	/**
+	 * URL property name.
+	 */
+	const PROP_URL = 'url';
+
+	/**
+	 * Type property name.
+	 */
+	const PROP_TYPE = 'type';
+
+	/**
+	 * Subtype property name.
+	 */
+	const PROP_SUBTYPE = 'subtype';
+
+	/**
+	 * Identifier for the 'any' type.
+	 */
+	const TYPE_ANY = 'any';
+
+	/**
+	 * Search handlers used by the controller.
+	 *
+	 * @since 5.0.0
+	 * @var array
+	 */
+	protected $search_handlers = array();
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param array $search_handlers List of search handlers to use in the controller. Each search
+	 *                               handler instance must extend the `WP_REST_Search_Handler` class.
+	 */
+	public function __construct( array $search_handlers ) {
+		$this->namespace = 'wp/v2';
+		$this->rest_base = 'search';
+
+		foreach ( $search_handlers as $search_handler ) {
+			if ( ! $search_handler instanceof WP_REST_Search_Handler ) {
+
+				/* translators: %s: PHP class name */
+				_doing_it_wrong( __METHOD__, sprintf( __( 'REST search handlers must extend the %s class.' ), 'WP_REST_Search_Handler' ), '5.0.0' );
+				continue;
+			}
+
+			$this->search_handlers[ $search_handler->get_type() ] = $search_handler;
+		}
+	}
+
+	/**
+	 * Registers the routes for the objects of the controller.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @see register_rest_route()
+	 */
+	public function register_routes() {
+		register_rest_route(
+			$this->namespace,
+			'/' . $this->rest_base,
+			array(
+				array(
+					'methods'             => WP_REST_Server::READABLE,
+					'callback'            => array( $this, 'get_items' ),
+					'permission_callback' => array( $this, 'get_items_permission_check' ),
+					'args'                => $this->get_collection_params(),
+				),
+				'schema' => array( $this, 'get_public_item_schema' ),
+			)
+		);
+	}
+
+	/**
+	 * Checks if a given request has access to search content.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return true|WP_Error True if the request has search access, WP_Error object otherwise.
+	 */
+	public function get_items_permission_check( $request ) {
+		return true;
+	}
+
+	/**
+	 * Retrieves a collection of search results.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
+	 */
+	public function get_items( $request ) {
+		$handler = $this->get_search_handler( $request );
+		if ( is_wp_error( $handler ) ) {
+			return $handler;
+		}
+
+		$result = $handler->search_items( $request );
+
+		if ( ! isset( $result[ WP_REST_Search_Handler::RESULT_IDS ] ) || ! is_array( $result[ WP_REST_Search_Handler::RESULT_IDS ] ) || ! isset( $result[ WP_REST_Search_Handler::RESULT_TOTAL ] ) ) {
+			return new WP_Error( 'rest_search_handler_error', __( 'Internal search handler error.' ), array( 'status' => 500 ) );
+		}
+
+		$ids = array_map( 'absint', $result[ WP_REST_Search_Handler::RESULT_IDS ] );
+
+		$results = array();
+		foreach ( $ids as $id ) {
+			$data      = $this->prepare_item_for_response( $id, $request );
+			$results[] = $this->prepare_response_for_collection( $data );
+		}
+
+		$total     = (int) $result[ WP_REST_Search_Handler::RESULT_TOTAL ];
+		$page      = (int) $request['page'];
+		$per_page  = (int) $request['per_page'];
+		$max_pages = ceil( $total / $per_page );
+
+		if ( $page > $max_pages && $total > 0 ) {
+			return new WP_Error( 'rest_search_invalid_page_number', __( 'The page number requested is larger than the number of pages available.' ), array( 'status' => 400 ) );
+		}
+
+		$response = rest_ensure_response( $results );
+		$response->header( 'X-WP-Total', $total );
+		$response->header( 'X-WP-TotalPages', $max_pages );
+
+		$request_params = $request->get_query_params();
+		$base           = add_query_arg( $request_params, rest_url( sprintf( '%s/%s', $this->namespace, $this->rest_base ) ) );
+
+		if ( $page > 1 ) {
+			$prev_link = add_query_arg( 'page', $page - 1, $base );
+			$response->link_header( 'prev', $prev_link );
+		}
+		if ( $page < $max_pages ) {
+			$next_link = add_query_arg( 'page', $page + 1, $base );
+			$response->link_header( 'next', $next_link );
+		}
+
+		return $response;
+	}
+
+	/**
+	 * Prepares a single search result for response.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param int             $id      ID of the item to prepare.
+	 * @param WP_REST_Request $request Request object.
+	 * @return WP_REST_Response Response object.
+	 */
+	public function prepare_item_for_response( $id, $request ) {
+		$handler = $this->get_search_handler( $request );
+		if ( is_wp_error( $handler ) ) {
+			return new WP_REST_Response();
+		}
+
+		$fields = $this->get_fields_for_response( $request );
+
+		$data = $handler->prepare_item( $id, $fields );
+		$data = $this->add_additional_fields_to_object( $data, $request );
+
+		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';
+		$data    = $this->filter_response_by_context( $data, $context );
+
+		$response = rest_ensure_response( $data );
+
+		$links               = $handler->prepare_item_links( $id );
+		$links['collection'] = array(
+			'href' => rest_url( sprintf( '%s/%s', $this->namespace, $this->rest_base ) ),
+		);
+		$response->add_links( $links );
+
+		return $response;
+	}
+
+	/**
+	 * Retrieves the item schema, conforming to JSON Schema.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @return array Item schema data.
+	 */
+	public function get_item_schema() {
+		$types    = array();
+		$subtypes = array();
+		foreach ( $this->search_handlers as $search_handler ) {
+			$types[]  = $search_handler->get_type();
+			$subtypes = array_merge( $subtypes, $search_handler->get_subtypes() );
+		}
+
+		$types    = array_unique( $types );
+		$subtypes = array_unique( $subtypes );
+
+		$schema = array(
+			'$schema'    => 'http://json-schema.org/draft-04/schema#',
+			'title'      => 'search-result',
+			'type'       => 'object',
+			'properties' => array(
+				self::PROP_ID      => array(
+					'description' => __( 'Unique identifier for the object.' ),
+					'type'        => 'integer',
+					'context'     => array( 'view', 'embed' ),
+					'readonly'    => true,
+				),
+				self::PROP_TITLE   => array(
+					'description' => __( 'The title for the object.' ),
+					'type'        => 'string',
+					'context'     => array( 'view', 'embed' ),
+					'readonly'    => true,
+				),
+				self::PROP_URL     => array(
+					'description' => __( 'URL to the object.' ),
+					'type'        => 'string',
+					'format'      => 'uri',
+					'context'     => array( 'view', 'embed' ),
+					'readonly'    => true,
+				),
+				self::PROP_TYPE    => array(
+					'description' => __( 'Object type.' ),
+					'type'        => 'string',
+					'enum'        => $types,
+					'context'     => array( 'view', 'embed' ),
+					'readonly'    => true,
+				),
+				self::PROP_SUBTYPE => array(
+					'description' => __( 'Object subtype.' ),
+					'type'        => 'string',
+					'enum'        => $subtypes,
+					'context'     => array( 'view', 'embed' ),
+					'readonly'    => true,
+				),
+			),
+		);
+
+		return $this->add_additional_fields_schema( $schema );
+	}
+
+	/**
+	 * Retrieves the query params for the search results collection.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @return array Collection parameters.
+	 */
+	public function get_collection_params() {
+		$types    = array();
+		$subtypes = array();
+		foreach ( $this->search_handlers as $search_handler ) {
+			$types[]  = $search_handler->get_type();
+			$subtypes = array_merge( $subtypes, $search_handler->get_subtypes() );
+		}
+
+		$types    = array_unique( $types );
+		$subtypes = array_unique( $subtypes );
+
+		$query_params = parent::get_collection_params();
+
+		$query_params['context']['default'] = 'view';
+
+		$query_params[ self::PROP_TYPE ] = array(
+			'default'     => $types[0],
+			'description' => __( 'Limit results to items of an object type.' ),
+			'type'        => 'string',
+			'enum'        => $types,
+		);
+
+		$query_params[ self::PROP_SUBTYPE ] = array(
+			'default'           => self::TYPE_ANY,
+			'description'       => __( 'Limit results to items of one or more object subtypes.' ),
+			'type'              => 'array',
+			'items'             => array(
+				'enum' => array_merge( $subtypes, array( self::TYPE_ANY ) ),
+				'type' => 'string',
+			),
+			'sanitize_callback' => array( $this, 'sanitize_subtypes' ),
+		);
+
+		return $query_params;
+	}
+
+	/**
+	 * Sanitizes the list of subtypes, to ensure only subtypes of the passed type are included.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param string|array    $subtypes  One or more subtypes.
+	 * @param WP_REST_Request $request   Full details about the request.
+	 * @param string          $parameter Parameter name.
+	 * @return array|WP_Error List of valid subtypes, or WP_Error object on failure.
+	 */
+	public function sanitize_subtypes( $subtypes, $request, $parameter ) {
+		$subtypes = wp_parse_slug_list( $subtypes );
+
+		$subtypes = rest_parse_request_arg( $subtypes, $request, $parameter );
+		if ( is_wp_error( $subtypes ) ) {
+			return $subtypes;
+		}
+
+		// 'any' overrides any other subtype.
+		if ( in_array( self::TYPE_ANY, $subtypes, true ) ) {
+			return array( self::TYPE_ANY );
+		}
+
+		$handler = $this->get_search_handler( $request );
+		if ( is_wp_error( $handler ) ) {
+			return $handler;
+		}
+
+		return array_intersect( $subtypes, $handler->get_subtypes() );
+	}
+
+	/**
+	 * Gets the search handler to handle the current request.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return WP_REST_Search_Handler|WP_Error Search handler for the request type, or WP_Error object on failure.
+	 */
+	protected function get_search_handler( $request ) {
+		$type = $request->get_param( self::PROP_TYPE );
+
+		if ( ! $type || ! isset( $this->search_handlers[ $type ] ) ) {
+			return new WP_Error( 'rest_search_invalid_type', __( 'Invalid type parameter.' ), array( 'status' => 400 ) );
+		}
+
+		return $this->search_handlers[ $type ];
+	}
+}
diff --git a/wp-includes/rest-api/search/class-wp-rest-post-search-handler.php b/wp-includes/rest-api/search/class-wp-rest-post-search-handler.php
new file mode 100644
index 0000000000..804be3b31b
--- /dev/null
+++ b/wp-includes/rest-api/search/class-wp-rest-post-search-handler.php
@@ -0,0 +1,192 @@
+<?php
+/**
+ * REST API: WP_REST_Post_Search_Handler class
+ *
+ * @package WordPress
+ * @subpackage REST_API
+ * @since 5.0.0
+ */
+
+/**
+ * Core class representing a search handler for posts in the REST API.
+ *
+ * @since 5.0.0
+ */
+class WP_REST_Post_Search_Handler extends WP_REST_Search_Handler {
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 5.0.0
+	 */
+	public function __construct() {
+		$this->type = 'post';
+
+		// Support all public post types except attachments.
+		$this->subtypes = array_diff(
+			array_values(
+				get_post_types(
+					array(
+						'public'       => true,
+						'show_in_rest' => true,
+					),
+					'names'
+				)
+			),
+			array( 'attachment' )
+		);
+	}
+
+	/**
+	 * Searches the object type content for a given search request.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_REST_Request $request Full REST request.
+	 * @return array Associative array containing an `WP_REST_Search_Handler::RESULT_IDS` containing
+	 *               an array of found IDs and `WP_REST_Search_Handler::RESULT_TOTAL` containing the
+	 *               total count for the matching search results.
+	 */
+	public function search_items( WP_REST_Request $request ) {
+
+		// Get the post types to search for the current request.
+		$post_types = $request[ WP_REST_Search_Controller::PROP_SUBTYPE ];
+		if ( in_array( WP_REST_Search_Controller::TYPE_ANY, $post_types, true ) ) {
+			$post_types = $this->subtypes;
+		}
+
+		$query_args = array(
+			'post_type'           => $post_types,
+			'post_status'         => 'publish',
+			'paged'               => (int) $request['page'],
+			'posts_per_page'      => (int) $request['per_page'],
+			'ignore_sticky_posts' => true,
+			'fields'              => 'ids',
+		);
+
+		if ( ! empty( $request['search'] ) ) {
+			$query_args['s'] = $request['search'];
+		}
+
+		$query     = new WP_Query();
+		$found_ids = $query->query( $query_args );
+		$total     = $query->found_posts;
+
+		return array(
+			self::RESULT_IDS   => $found_ids,
+			self::RESULT_TOTAL => $total,
+		);
+	}
+
+	/**
+	 * Prepares the search result for a given ID.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param int   $id     Item ID.
+	 * @param array $fields Fields to include for the item.
+	 * @return array Associative array containing all fields for the item.
+	 */
+	public function prepare_item( $id, array $fields ) {
+		$post = get_post( $id );
+
+		$data = array();
+
+		if ( in_array( WP_REST_Search_Controller::PROP_ID, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_ID ] = (int) $post->ID;
+		}
+
+		if ( in_array( WP_REST_Search_Controller::PROP_TITLE, $fields, true ) ) {
+			if ( post_type_supports( $post->post_type, 'title' ) ) {
+				add_filter( 'protected_title_format', array( $this, 'protected_title_format' ) );
+				$data[ WP_REST_Search_Controller::PROP_TITLE ] = get_the_title( $post->ID );
+				remove_filter( 'protected_title_format', array( $this, 'protected_title_format' ) );
+			} else {
+				$data[ WP_REST_Search_Controller::PROP_TITLE ] = '';
+			}
+		}
+
+		if ( in_array( WP_REST_Search_Controller::PROP_URL, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_URL ] = get_permalink( $post->ID );
+		}
+
+		if ( in_array( WP_REST_Search_Controller::PROP_TYPE, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_TYPE ] = $this->type;
+		}
+
+		if ( in_array( WP_REST_Search_Controller::PROP_SUBTYPE, $fields, true ) ) {
+			$data[ WP_REST_Search_Controller::PROP_SUBTYPE ] = $post->post_type;
+		}
+
+		return $data;
+	}
+
+	/**
+	 * Prepares links for the search result of a given ID.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param int $id Item ID.
+	 * @return array Links for the given item.
+	 */
+	public function prepare_item_links( $id ) {
+		$post = get_post( $id );
+
+		$links = array();
+
+		$item_route = $this->detect_rest_item_route( $post );
+		if ( ! empty( $item_route ) ) {
+			$links['self'] = array(
+				'href'       => rest_url( $item_route ),
+				'embeddable' => true,
+			);
+		}
+
+		$links['about'] = array(
+			'href' => rest_url( 'wp/v2/types/' . $post->post_type ),
+		);
+
+		return $links;
+	}
+
+	/**
+	 * Overwrites the default protected title format.
+	 *
+	 * By default, WordPress will show password protected posts with a title of
+	 * "Protected: %s". As the REST API communicates the protected status of a post
+	 * in a machine readable format, we remove the "Protected: " prefix.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @return string Protected title format.
+	 */
+	public function protected_title_format() {
+		return '%s';
+	}
+
+	/**
+	 * Attempts to detect the route to access a single item.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_Post $post Post object.
+	 * @return string REST route relative to the REST base URI, or empty string if unknown.
+	 */
+	protected function detect_rest_item_route( $post ) {
+		$post_type = get_post_type_object( $post->post_type );
+		if ( ! $post_type ) {
+			return '';
+		}
+
+		// It's currently impossible to detect the REST URL from a custom controller.
+		if ( ! empty( $post_type->rest_controller_class ) && 'WP_REST_Posts_Controller' !== $post_type->rest_controller_class ) {
+			return '';
+		}
+
+		$namespace = 'wp/v2';
+		$rest_base = ! empty( $post_type->rest_base ) ? $post_type->rest_base : $post_type->name;
+
+		return sprintf( '%s/%s/%d', $namespace, $rest_base, $post->ID );
+	}
+
+}
diff --git a/wp-includes/rest-api/search/class-wp-rest-search-handler.php b/wp-includes/rest-api/search/class-wp-rest-search-handler.php
new file mode 100644
index 0000000000..4799e1c981
--- /dev/null
+++ b/wp-includes/rest-api/search/class-wp-rest-search-handler.php
@@ -0,0 +1,97 @@
+<?php
+/**
+ * REST API: WP_REST_Search_Handler class
+ *
+ * @package WordPress
+ * @subpackage REST_API
+ * @since 5.0.0
+ */
+
+/**
+ * Core base class representing a search handler for an object type in the REST API.
+ *
+ * @since 5.0.0
+ */
+abstract class WP_REST_Search_Handler {
+
+	/**
+	 * Field containing the IDs in the search result.
+	 */
+	const RESULT_IDS = 'ids';
+
+	/**
+	 * Field containing the total count in the search result.
+	 */
+	const RESULT_TOTAL = 'total';
+
+	/**
+	 * Object type managed by this search handler.
+	 *
+	 * @since 5.0.0
+	 * @var string
+	 */
+	protected $type = '';
+
+	/**
+	 * Object subtypes managed by this search handler.
+	 *
+	 * @since 5.0.0
+	 * @var array
+	 */
+	protected $subtypes = array();
+
+	/**
+	 * Gets the object type managed by this search handler.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @return string Object type identifier.
+	 */
+	public function get_type() {
+		return $this->type;
+	}
+
+	/**
+	 * Gets the object subtypes managed by this search handler.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @return array Array of object subtype identifiers.
+	 */
+	public function get_subtypes() {
+		return $this->subtypes;
+	}
+
+	/**
+	 * Searches the object type content for a given search request.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param WP_REST_Request $request Full REST request.
+	 * @return array Associative array containing an `WP_REST_Search_Handler::RESULT_IDS` containing
+	 *               an array of found IDs and `WP_REST_Search_Handler::RESULT_TOTAL` containing the
+	 *               total count for the matching search results.
+	 */
+	abstract public function search_items( WP_REST_Request $request );
+
+	/**
+	 * Prepares the search result for a given ID.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param int   $id     Item ID.
+	 * @param array $fields Fields to include for the item.
+	 * @return array Associative array containing all fields for the item.
+	 */
+	abstract public function prepare_item( $id, array $fields );
+
+	/**
+	 * Prepares links for the search result of a given ID.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param int $id Item ID.
+	 * @return array Links for the given item.
+	 */
+	abstract public function prepare_item_links( $id );
+}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 97a687454b..eba953f756 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44048';
+$wp_version = '5.1-alpha-44107';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
diff --git a/wp-settings.php b/wp-settings.php
index 8646b60aed..6e93f7b6e8 100644
--- a/wp-settings.php
+++ b/wp-settings.php
@@ -234,6 +234,7 @@ require( ABSPATH . WPINC . '/rest-api/endpoints/class-wp-rest-taxonomies-control
 require( ABSPATH . WPINC . '/rest-api/endpoints/class-wp-rest-terms-controller.php' );
 require( ABSPATH . WPINC . '/rest-api/endpoints/class-wp-rest-users-controller.php' );
 require( ABSPATH . WPINC . '/rest-api/endpoints/class-wp-rest-comments-controller.php' );
+require( ABSPATH . WPINC . '/rest-api/endpoints/class-wp-rest-search-controller.php' );
 require( ABSPATH . WPINC . '/rest-api/endpoints/class-wp-rest-settings-controller.php' );
 require( ABSPATH . WPINC . '/rest-api/endpoints/class-wp-rest-themes-controller.php' );
 require( ABSPATH . WPINC . '/rest-api/fields/class-wp-rest-meta-fields.php' );
@@ -241,6 +242,8 @@ require( ABSPATH . WPINC . '/rest-api/fields/class-wp-rest-comment-meta-fields.p
 require( ABSPATH . WPINC . '/rest-api/fields/class-wp-rest-post-meta-fields.php' );
 require( ABSPATH . WPINC . '/rest-api/fields/class-wp-rest-term-meta-fields.php' );
 require( ABSPATH . WPINC . '/rest-api/fields/class-wp-rest-user-meta-fields.php' );
+require( ABSPATH . WPINC . '/rest-api/search/class-wp-rest-search-handler.php' );
+require( ABSPATH . WPINC . '/rest-api/search/class-wp-rest-post-search-handler.php' );
 
 $GLOBALS['wp_embed'] = new WP_Embed();