diff --git a/packages/@stylexjs/unplugin/src/core.js b/packages/@stylexjs/unplugin/src/core.js
index 340af13cf..53b22f18b 100644
--- a/packages/@stylexjs/unplugin/src/core.js
+++ b/packages/@stylexjs/unplugin/src/core.js
@@ -283,6 +283,7 @@ export const unpluginFactory = (userOptions = {}, metaOptions) => {
   async function runBabelTransform(inputCode, filename, callerName) {
     const result = await transformAsync(inputCode, {
       babelrc: false,
+      configFile: false,
       filename,
       presets,
       plugins: [
diff --git a/packages/@stylexjs/unplugin/src/vite.js b/packages/@stylexjs/unplugin/src/vite.js
index 9510369c0..3d0c85494 100644
--- a/packages/@stylexjs/unplugin/src/vite.js
+++ b/packages/@stylexjs/unplugin/src/vite.js
@@ -87,6 +87,10 @@ function attachViteHooks(plugin) {
             } catch {}
           }
         }, 150);
+        // Unref the timer so it does not prevent the process from exiting
+        // (e.g. when Vitest runs the plugin in middleware mode without an
+        // HTTP server that emits 'close').
+        interval.unref();
         server.httpServer?.once('close', () => clearInterval(interval));
       }
     },