Index: src/wp-includes/js/wp-api.js
===================================================================
--- src/wp-includes/js/wp-api.js	(revision 42657)
+++ src/wp-includes/js/wp-api.js	(working copy)
@@ -993,10 +993,9 @@
 				options    = options || {};
 				beforeSend = options.beforeSend;
 
-				// If we have a localized nonce, pass that along with each sync.
-				if ( 'undefined' !== typeof wpApiSettings.nonce ) {
+				if ( _.isFunction( model.nonce ) && ! _.isUndefined( model.nonce() ) && ! _.isNull( model.nonce() ) ) {
 					options.beforeSend = function( xhr ) {
-						xhr.setRequestHeader( 'X-WP-Nonce', wpApiSettings.nonce );
+						xhr.setRequestHeader( 'X-WP-Nonce', model.nonce() );
 
 						if ( beforeSend ) {
 							return beforeSend.apply( self, arguments );
@@ -1405,6 +1404,11 @@
 							return new loadingObjects.models[ modelClassName ]( attrs, options );
 						},
 
+						// Track nonces at the Endpoint level.
+						nonce: function() {
+							return routeModel.get( 'nonce' );
+						},
+
 						// Include a reference to the original class name.
 						name: collectionClassName,
 
@@ -1432,6 +1436,11 @@
 							return new loadingObjects.models[ modelClassName ]( attrs, options );
 						},
 
+						// Track nonces at the Endpoint level.
+						nonce: function() {
+							return routeModel.get( 'nonce' );
+						},
+
 						// Include a reference to the original class name.
 						name: collectionClassName,