diff --git a/.changeset/hot-pandas-tan.md b/.changeset/hot-pandas-tan.md
new file mode 100644
index 0000000..2896900
--- /dev/null
+++ b/.changeset/hot-pandas-tan.md
@@ -0,0 +1,5 @@
+---
+"vite-plugin-static-copy": patch
+---
+
+send headers set by `server.headers` in dev
diff --git a/src/middleware.ts b/src/middleware.ts
index 599c133..5628ab8 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -12,7 +12,7 @@ import { parse } from '@polka/url'
 import { lookup } from 'mrmime'
 import type { Stats } from 'node:fs'
 import { statSync, createReadStream, existsSync } from 'node:fs'
-import type { Connect } from 'vite'
+import type { Connect, ServerOptions } from 'vite'
 import type {
   IncomingMessage,
   OutgoingHttpHeaders,
@@ -205,17 +205,13 @@ function sendStatic(
   createReadStream(file, opts).pipe(res)
 }
 
-async function sendTransform(
+function sendTransform(
   req: IncomingMessage,
   res: ServerResponse,
   file: string,
-  transform: TransformOptionObject
-): Promise<boolean> {
-  const transformedContent = await getTransformedContent(file, transform)
-  if (transformedContent === null) {
-    return false
-  }
-
+  transform: TransformOptionObject,
+  transformedContent: string | Buffer
+): void {
   const transformHeaders = getTransformHeaders(
     file,
     transform.encoding,
@@ -225,7 +221,7 @@ async function sendTransform(
   if (req.headers['if-none-match'] === transformHeaders['ETag']) {
     res.writeHead(304)
     res.end()
-    return true
+    return
   }
 
   const code = 200
@@ -233,7 +229,28 @@ async function sendTransform(
 
   res.writeHead(code, headers)
   res.end(transformedContent)
-  return true
+  return
+}
+
+function setHeaders(
+  res: ServerResponse,
+  pathname: string,
+  headers: OutgoingHttpHeaders | undefined
+) {
+  // Matches js, jsx, ts, tsx.
+  // The reason this is done, is that the .ts file extension is reserved
+  // for the MIME type video/mp2t. In almost all cases, we can expect
+  // these files to be TypeScript files, and for Vite to serve them with
+  // this Content-Type.
+  if (/\.[tj]sx?$/.test(pathname)) {
+    res.setHeader('Content-Type', 'application/javascript')
+  }
+
+  if (headers) {
+    for (const name in headers) {
+      res.setHeader(name, headers[name]!)
+    }
+  }
 }
 
 function return404(res: ServerResponse, next: Connect.NextFunction) {
@@ -246,7 +263,11 @@ function return404(res: ServerResponse, next: Connect.NextFunction) {
 }
 
 export function serveStaticCopyMiddleware(
-  { root, publicDir }: { root: string; publicDir: string },
+  {
+    root,
+    publicDir,
+    server
+  }: { root: string; publicDir: string; server: ServerOptions },
   fileMap: FileMap
 ): Connect.NextHandleFunction {
   // Keep the named function. The name is visible in debug logs via `DEBUG=connect:dispatcher ...`
@@ -267,30 +288,29 @@ export function serveStaticCopyMiddleware(
         return
       }
 
-      // Matches js, jsx, ts, tsx.
-      // The reason this is done, is that the .ts file extension is reserved
-      // for the MIME type video/mp2t. In almost all cases, we can expect
-      // these files to be TypeScript files, and for Vite to serve them with
-      // this Content-Type.
-      if (/\.[tj]sx?$/.test(pathname)) {
-        res.setHeader('Content-Type', 'application/javascript')
-      }
-
       const transformOption = resolveTransformOption(data.transform)
       if (transformOption) {
-        const sent = await sendTransform(
-          req,
-          res,
+        const transformedContent = await getTransformedContent(
           data.filepath,
           transformOption
         )
-        if (!sent) {
+        if (transformedContent === null) {
           return404(res, next)
           return
         }
+
+        setHeaders(res, pathname, server.headers)
+        sendTransform(
+          req,
+          res,
+          data.filepath,
+          transformOption,
+          transformedContent
+        )
         return
       }
 
+      setHeaders(res, pathname, server.headers)
       sendStatic(req, res, data.filepath, data.stats)
     } catch (e) {
       if (e instanceof Error) {
diff --git a/test/fixtures/vite.other.config.ts b/test/fixtures/vite.other.config.ts
index a39598a..74c483c 100644
--- a/test/fixtures/vite.other.config.ts
+++ b/test/fixtures/vite.other.config.ts
@@ -3,6 +3,12 @@ import { viteStaticCopy } from 'vite-plugin-static-copy'
 
 export default defineConfig({
   appType: 'custom', // disable SPA/MPA fallback
+  server: {
+    headers: {
+      'Cross-Origin-Embedder-Policy': 'require-corp',
+      'Cross-Origin-Opener-Policy': 'same-origin'
+    }
+  },
   plugins: [
     viteStaticCopy({
       targets: [
diff --git a/test/tests.test.ts b/test/tests.test.ts
index 3ae0575..838f01f 100644
--- a/test/tests.test.ts
+++ b/test/tests.test.ts
@@ -77,6 +77,15 @@ describe('serve', () => {
       expect(res.status).toBe(200)
       expect(res.headers.get('Access-Control-Allow-Origin')).toBe('*')
     })
+
+    test.concurrent('headers', async () => {
+      const res = await fetchFromServer(server, '/fixture1/foo.txt')
+      expect(res.status).toBe(200)
+      expect(res.headers.get('Cross-Origin-Embedder-Policy')).toBe(
+        'require-corp'
+      )
+      expect(res.headers.get('Cross-Origin-Opener-Policy')).toBe('same-origin')
+    })
   })
 })