diff --git a/scripts/dev-server.js b/scripts/dev-server.js
index 713771302..a8be25a31 100644
--- a/scripts/dev-server.js
+++ b/scripts/dev-server.js
@@ -17,7 +17,7 @@ const server = http.createServer(async (request, response) => {
 	const jsFiles = ['morebits.js', 'twinkle.js'].concat(moduleFiles.map(f => 'modules/' + f));
 	const cssFiles = ['morebits.css', 'twinkle.css'];
 
-	let jsCode = `mw.loader.load(['jquery.ui', 'ext.gadget.select2']);`;
+	let jsCode = `mw.loader.using(['jquery.ui', 'ext.gadget.select2']).then(function () {\n`;
 
 	if (process.argv[2] !== '--no-sysop') {
 		// Pretend to be a sysop, if not one already - enables testing of sysop modules by non-sysops
@@ -33,6 +33,7 @@ const server = http.createServer(async (request, response) => {
 		jsCode += `;mw.loader.addStyleTag(${css});`;
 	}
 	jsCode += `;console.log('Loaded debug version of Twinkle.');`;
+	jsCode += `});`; // End mw.loader.using
 	response.writeHead(200, { 'Content-Type': 'text/javascript; charset=utf-8' });
 	response.end(jsCode, 'utf-8');
 });