diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
index 4707dd4a62..2612f66c9f 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
@@ -188,6 +188,18 @@ class WP_REST_Attachments_Controller extends WP_REST_Posts_Controller {
 		}
 
 		$request->set_param( 'context', 'edit' );
+
+		/**
+		 * Fires after a single attachment is completely created or updated via the REST API.
+		 *
+		 * @since 5.0.0
+		 *
+		 * @param WP_Post         $attachment Inserted or updated attachment object.
+		 * @param WP_REST_Request $request    Request object.
+		 * @param bool            $creating   True when creating an attachment, false when updating.
+		 */
+		do_action( 'rest_after_insert_attachment', $attachment, $request, true );
+
 		$response = $this->prepare_item_for_response( $attachment, $request );
 		$response = rest_ensure_response( $response );
 		$response->set_status( 201 );
@@ -234,6 +246,10 @@ class WP_REST_Attachments_Controller extends WP_REST_Posts_Controller {
 		}
 
 		$request->set_param( 'context', 'edit' );
+
+		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php */
+		do_action( 'rest_after_insert_attachment', $attachment, $request, false );
+
 		$response = $this->prepare_item_for_response( $attachment, $request );
 		$response = rest_ensure_response( $response );
 
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
index 05227a1d5f..f673450d41 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
@@ -633,9 +633,20 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 		}
 
 		$context = current_user_can( 'moderate_comments' ) ? 'edit' : 'view';
-
 		$request->set_param( 'context', $context );
 
+		/**
+		 * Fires completely after a comment is created or updated via the REST API.
+		 *
+		 * @since 5.0.0
+		 *
+		 * @param WP_Comment      $comment  Inserted or updated comment object.
+		 * @param WP_REST_Request $request  Request object.
+		 * @param bool            $creating True when creating a comment, false
+		 *                                  when updating.
+		 */
+		do_action( 'rest_after_insert_comment', $comment, $request, true );
+
 		$response = $this->prepare_item_for_response( $comment, $request );
 		$response = rest_ensure_response( $response );
 
@@ -757,6 +768,9 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 
 		$request->set_param( 'context', 'edit' );
 
+		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php */
+		do_action( 'rest_after_insert_comment', $comment, $request, false );
+
 		$response = $this->prepare_item_for_response( $comment, $request );
 
 		return rest_ensure_response( $response );
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
index 93b6608e7a..5002484ed8 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
@@ -608,6 +608,19 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 
 		$request->set_param( 'context', 'edit' );
 
+		/**
+		 * Fires after a single post is completely created or updated via the REST API.
+		 *
+		 * The dynamic portion of the hook name, `$this->post_type`, refers to the post type slug.
+		 *
+		 * @since 5.0.0
+		 *
+		 * @param WP_Post         $post     Inserted or updated post object.
+		 * @param WP_REST_Request $request  Request object.
+		 * @param bool            $creating True when creating a post, false when updating.
+		 */
+		do_action( "rest_after_insert_{$this->post_type}", $post, $request, true );
+
 		$response = $this->prepare_item_for_response( $post, $request );
 		$response = rest_ensure_response( $response );
 
@@ -734,6 +747,9 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 
 		$request->set_param( 'context', 'edit' );
 
+		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php */
+		do_action( "rest_after_insert_{$this->post_type}", $post, $request, false );
+
 		$response = $this->prepare_item_for_response( $post, $request );
 
 		return rest_ensure_response( $response );
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php
index 884e5f60f3..ff399cc60e 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php
@@ -469,6 +469,19 @@ class WP_REST_Terms_Controller extends WP_REST_Controller {
 
 		$request->set_param( 'context', 'view' );
 
+		/**
+		 * Fires after a single term is completely created or updated via the REST API.
+		 *
+		 * The dynamic portion of the hook name, `$this->taxonomy`, refers to the taxonomy slug.
+		 *
+		 * @since 5.0.0
+		 *
+		 * @param WP_Term         $term     Inserted or updated term object.
+		 * @param WP_REST_Request $request  Request object.
+		 * @param bool            $creating True when creating a term, false when updating.
+		 */
+		do_action( "rest_after_insert_{$this->taxonomy}", $term, $request, true );
+
 		$response = $this->prepare_item_for_response( $term, $request );
 		$response = rest_ensure_response( $response );
 
@@ -558,6 +571,9 @@ class WP_REST_Terms_Controller extends WP_REST_Controller {
 
 		$request->set_param( 'context', 'view' );
 
+		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php */
+		do_action( "rest_after_insert_{$this->taxonomy}", $term, $request, false );
+
 		$response = $this->prepare_item_for_response( $term, $request );
 
 		return rest_ensure_response( $response );
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
index ec3f9ea204..6c9611c87b 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
@@ -566,6 +566,17 @@ class WP_REST_Users_Controller extends WP_REST_Controller {
 
 		$request->set_param( 'context', 'edit' );
 
+		/**
+		 * Fires after a user is completely created or updated via the REST API.
+		 *
+		 * @since 5.0.0
+		 *
+		 * @param WP_User         $user     Inserted or updated user object.
+		 * @param WP_REST_Request $request  Request object.
+		 * @param bool            $creating True when creating a user, false when updating.
+		 */
+		do_action( 'rest_after_insert_user', $user, $request, true );
+
 		$response = $this->prepare_item_for_response( $user, $request );
 		$response = rest_ensure_response( $response );
 
@@ -689,6 +700,9 @@ class WP_REST_Users_Controller extends WP_REST_Controller {
 
 		$request->set_param( 'context', 'edit' );
 
+		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php */
+		do_action( 'rest_after_insert_user', $user, $request, false );
+
 		$response = $this->prepare_item_for_response( $user, $request );
 		$response = rest_ensure_response( $response );
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 6707a3cb06..4edb8eb06d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-43986';
+$wp_version = '5.1-alpha-43987';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.