diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 36b59ac8e1..ca91c53e00 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -2975,6 +2975,15 @@ function wp_die( $message = '', $title = '', $args = array() ) {
 		 * @param callable $function Callback function name.
 		 */
 		$function = apply_filters( 'wp_die_ajax_handler', '_ajax_wp_die_handler' );
+	} elseif ( wp_is_json_request() ) {
+		/**
+		 * Filters the callback for killing WordPress execution for JSON requests.
+		 *
+		 * @since 5.1.0
+		 *
+		 * @param callable $function Callback function name.
+		 */
+		$function = apply_filters( 'wp_die_json_handler', '_json_wp_die_handler' );
 	} elseif ( defined( 'XMLRPC_REQUEST' ) && XMLRPC_REQUEST ) {
 		/**
 		 * Filters the callback for killing WordPress execution for XML-RPC requests.
@@ -3215,6 +3224,40 @@ function _default_wp_die_handler( $message, $title = '', $args = array() ) {
 	die();
 }
 
+/**
+ * Kill WordPress execution and display JSON message with error message.
+ *
+ * This is the handler for wp_die when processing JSON requests.
+ *
+ * @since 5.1.0
+ * @access private
+ *
+ * @param string       $message Error message.
+ * @param string       $title   Optional. Error title. Default empty.
+ * @param string|array $args    Optional. Arguments to control behavior. Default empty array.
+ */
+function _json_wp_die_handler( $message, $title = '', $args = array() ) {
+	$defaults = array( 'response' => 500 );
+
+	$r = wp_parse_args( $args, $defaults );
+
+	$data = array(
+		'code'    => 'wp_die',
+		'message' => $message,
+		'status'  => $r['response'],
+	);
+
+	if ( ! headers_sent() ) {
+		header( 'Content-Type: application/json; charset=utf-8' );
+		if ( null !== $r['response'] ) {
+			status_header( $r['response'] );
+		}
+	}
+
+	echo wp_json_encode( $data );
+	die();
+}
+
 /**
  * Kill WordPress execution and display XML message with error message.
  *
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 01d9a2f04e..1c2a84bb67 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-beta1-44624';
+$wp_version = '5.1-beta1-44625';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.