diff --git a/resources/mediawiki.d.ts b/resources/mediawiki.d.ts
index 7d488caaa..ff2558334 100644
--- a/resources/mediawiki.d.ts
+++ b/resources/mediawiki.d.ts
@@ -43,8 +43,12 @@ interface MediaWiki {
 		 * Execute a function after one or more modules are ready.
 		 * 
 		 * @param moduleName 
+		 * @param {Function} ready Callback to execute when all dependencies are
+		 * ready.
+		 * @param {Function} after Callback to execute if one or more dependencies
+		 * failed.
 		 */
-		using( moduleName: string|null ): JQuery.Promise<any>;
+		using( moduleName: string|null, ready?: Function, error?: Function ): JQuery.Promise<any>;
 		
 		/**
 		 * Load a given resourceLoader module.
diff --git a/resources/skins.vector.js/searchLoader.js b/resources/skins.vector.js/searchLoader.js
index 427081b11..074e56cab 100644
--- a/resources/skins.vector.js/searchLoader.js
+++ b/resources/skins.vector.js/searchLoader.js
@@ -11,6 +11,17 @@
 
 var /** @type {VectorResourceLoaderVirtualConfig} */
 	config = require( /** @type {string} */ ( './config.json' ) ),
+	// T251544: Collect search performance metrics to compare Vue search with
+	// mediawiki.searchSuggest performance.
+	SHOULD_TEST_SEARCH = !!(
+		!config.wgVectorUseCoreSearch &&
+		window.performance &&
+		performance.mark &&
+		performance.measure &&
+		performance.getEntriesByName ),
+	LOAD_START_MARK = 'mwVectorVueSearchLoadStart',
+	LOAD_END_MARK = 'mwVectorVueSearchLoadEnd',
+	LOAD_MEASURE = 'mwVectorVueSearchLoadStartToLoadEnd',
 	SEARCH_FORM_ID = 'simpleSearch',
 	SEARCH_INPUT_ID = 'searchInput',
 	SEARCH_LOADING_CLASS = 'search-form__loader',
@@ -32,7 +43,10 @@ var /** @type {VectorResourceLoaderVirtualConfig} */
 function loadSearchModule( element, moduleName, afterLoadFn ) {
 
 	function requestSearchModule() {
-		mw.loader.using( moduleName ).then( afterLoadFn );
+		if ( SHOULD_TEST_SEARCH ) {
+			performance.mark( LOAD_START_MARK );
+		}
+		mw.loader.using( moduleName, afterLoadFn );
 		element.removeEventListener( 'focus', requestSearchModule );
 	}
 
@@ -101,6 +115,16 @@ function setLoadingIndicatorListeners( element, attach, eventCallback ) {
 	}
 }
 
+/**
+ * Marks when the lazy load has completed.
+ */
+function markLoadEnd() {
+	if ( SHOULD_TEST_SEARCH && performance.getEntriesByName( LOAD_START_MARK ).length ) {
+		performance.mark( LOAD_END_MARK );
+		performance.measure( LOAD_MEASURE, LOAD_START_MARK, LOAD_END_MARK );
+	}
+}
+
 /**
  * Initialize the loading of the search module as well as the loading indicator.
  * Only initialize the loading indicator when not using the core search module.
@@ -128,9 +152,17 @@ function initSearchLoader( document ) {
 		loadSearchModule(
 			searchInput,
 			SEARCH_MODULE_NAME,
-			setLoadingIndicatorListeners.bind( null,
-				searchForm, false, renderSearchLoadingIndicator )
+			function () {
+				markLoadEnd();
+
+				setLoadingIndicatorListeners(
+					/** @type {HTMLElement} */ ( searchForm ),
+					false,
+					renderSearchLoadingIndicator
+				);
+			}
 		);
+
 	}
 }