diff --git a/lib/index.js b/lib/index.js
index 0ab7b71..ea82d2c 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -15,9 +15,9 @@ const serverPath = isWindows ? serverFile.replaceAll("\\", "//") : serverFile;
 * @typedef {import('astro').AstroUserConfig} AstroUserConfig
 @typedef {import('astro').AstroConfig} AstroConfig
 * @typedef {import('vite').Plugin} VitePlugin
-* 
+*
 * @typedef {import('./types').IntegrationOptions} IntegrationOptions
-* 
+*
 */
 
 /**
@@ -38,42 +38,42 @@ function vitePlugin(options) {
   return {
     name: '@matthewp/astro-fastify:vite',
     async configureServer(server) {
-      const nextSymbol = Symbol('next');
-      
-      /** @type {import('fastify').FastifyServerFactory} */
-      const serverFactory = (handler, opts) => {
-        server.middlewares.use((req, res, next) => {
-          req[nextSymbol] = next;
-          handler(req, res);
+      return async () => {
+        const nextSymbol = Symbol('next');
+        /** @type {import('fastify').FastifyServerFactory} */
+        const serverFactory = (handler, opts) => {
+          server.middlewares.use((req, res, next) => {
+            req[nextSymbol] = next;
+            handler(req, res);
+          });
+          return /** @type {import('http').Server} */(server.httpServer ?? new http.Server());
+        }
+
+        const fastify = Fastify({
+          logger: options?.logger ?? true,
+          serverFactory
         });
-        return /** @type {import('http').Server} */(server.httpServer ?? new http.Server());
-      }
-      
-      const fastify = Fastify({
-        logger: options?.logger ?? true,
-        serverFactory
-      });
-      
-      if(options?.entry) {
-        const entry = entryToPath(options.entry);
-        const entryModule = await server.ssrLoadModule(entry);
-        const setupRoutes = entryModule.default;
-        if(typeof setupRoutes !== 'function') {
-          throw new Error(`@matthewp/astro-fastify: ${entry} should export a default function.`);
+
+        if(options?.entry) {
+          const entry = entryToPath(options.entry);
+          const entryModule = await server.ssrLoadModule(entry);
+          const setupRoutes = entryModule.default;
+          if(typeof setupRoutes !== 'function') {
+            throw new Error(`@matthewp/astro-fastify: ${entry} should export a default function.`);
+          }
+          setupRoutes(fastify);
         }
-        setupRoutes(fastify);
+
+        // Final catch-all route forwards back to the Vite server
+        fastify.all('/*', function (request) {
+          /** @type {import('connect').NextFunction} */
+          const next = request.raw[nextSymbol];
+          if (typeof next === "function") {
+            next();
+          }
+        });
+        await fastify.ready();
       }
-      
-      // Final catch-all route forwards back to the Vite server
-      fastify.all('/*', function (request) {
-        /** @type {import('connect').NextFunction} */
-        const next = request.raw[nextSymbol];
-        if (typeof next === "function") {
-          next();
-        }
-      });
-      
-      await fastify.ready();
     },
     transform(code, id) {
       if(options?.entry && id.includes('@matthewp/astro-fastify/lib/server.js')) {