diff --git a/src/Request.ts b/src/Request.ts
index ee38d70..e3afb45 100644
--- a/src/Request.ts
+++ b/src/Request.ts
@@ -169,6 +169,12 @@ export class Request {
     public async text(): Promise<string> {
         return (await this.blob()).text();
     }
+
+    /**
+     * Response headers that the Response to this request should include.
+     * @internal
+     */
+    public _responseHeaders = new Headers();
 }
 
 export namespace Request {
diff --git a/src/Server.ts b/src/Server.ts
index b9b476a..81e3b49 100644
--- a/src/Server.ts
+++ b/src/Server.ts
@@ -36,8 +36,12 @@ class Server {
         this.server.listen(options.port);
     }
 
+    /** @internal **/
+    public get _keepAliveTimeout() {
+        return this.server.keepAliveTimeout;
+    }
+
     private async listener(req: http.IncomingMessage, res: http.ServerResponse) {
-        res.setHeaders(this.globalHeaders);
         let apiRequest: Request;
         try {
             apiRequest = Request.incomingMessage(req);
@@ -52,11 +56,13 @@ class Server {
             throw e;
         }
 
+        for (const [key, value] of this.globalHeaders)
+            apiRequest._responseHeaders.set(key, value);
+
         if (this.copyOrigin) {
-            res.appendHeader("Access-Control-Allow-Origin", apiRequest.headers.get("Origin") ?? "*");
-            res.appendHeader("Vary", "Origin");
+            apiRequest._responseHeaders.set("access-control-allow-origin", apiRequest.headers.get("Origin") ?? "*");
+            apiRequest._responseHeaders.set("vary", "origin");
         }
-        res.setHeaders(this.globalHeaders);
 
         let response: Response;
         try {
diff --git a/src/response/BufferResponse.ts b/src/response/BufferResponse.ts
index ad4e833..fca0a72 100644
--- a/src/response/BufferResponse.ts
+++ b/src/response/BufferResponse.ts
@@ -1,4 +1,6 @@
 import http from "node:http";
+import {Request} from "../Request.js";
+import {Server} from "../Server.js";
 import {Response} from "./Response.js";
 
 /**
@@ -10,9 +12,15 @@ export abstract class BufferResponse extends Response {
      */
     protected abstract readBuffer(): Uint8Array | Promise<Uint8Array>;
 
-    protected override async send(res: http.ServerResponse): Promise<void> {
-        this.writeHead(res);
+    protected override async send(res: http.ServerResponse, server: Server, req?: Request): Promise<void> {
         const buffer = await this.readBuffer();
+        if (req !== undefined) {
+            if (res.chunkedEncoding)
+                req._responseHeaders.set("transfer-encoding", "chunked");
+            else
+                req._responseHeaders.set("content-length", buffer.byteLength.toString());
+        }
+        this.writeHead(res, server, req);
         res.end(buffer);
     }
 }
diff --git a/src/response/EmptyResponse.ts b/src/response/EmptyResponse.ts
index 9028707..536a2f6 100644
--- a/src/response/EmptyResponse.ts
+++ b/src/response/EmptyResponse.ts
@@ -1,4 +1,6 @@
 import http from "node:http";
+import {Request} from "../Request.js";
+import {Server} from "../Server.js";
 import {Response} from "./Response.js";
 
 /**
@@ -14,8 +16,15 @@ export class EmptyResponse extends Response {
         super(status, headers);
     }
 
-    protected override send(res: http.ServerResponse): void {
+    /*protected override send(res: http.ServerResponse): void {
         this.writeHead(res);
         res.end();
+    }*/
+
+    protected override send(res: http.ServerResponse, server: Server, req?: Request): void {
+        if (req !== undefined)
+            req._responseHeaders.set("content-length", "0");
+        this.writeHead(res, server, req);
+        res.end();
     }
 }
diff --git a/src/response/Response.ts b/src/response/Response.ts
index 1feb840..b9aef60 100644
--- a/src/response/Response.ts
+++ b/src/response/Response.ts
@@ -36,9 +36,27 @@ export abstract class Response {
     /**
      * Set the HTTP response status code and headers.
      */
-    protected writeHead(res: http.ServerResponse) {
-        res.statusCode = this.statusCode;
-        res.setHeaders(this.headers);
+    protected writeHead(res: http.ServerResponse, server: Server, req?: Request) {
+        const headers = new Headers(this.headers);
+        if (req !== undefined)
+            for (const [key, value] of req._responseHeaders)
+                headers.set(key, value);
+        if (!headers.has("date"))
+            headers.set("date", new Date().toUTCString());
+        if (
+            req === undefined
+            || req.headers.get("connection") === "close"
+            || !res.shouldKeepAlive
+        )
+            headers.set("connection", "close");
+        else {
+            headers.set("connection", "keep-alive");
+            headers.set("keep-alive", "timeout=" + server._keepAliveTimeout);
+        }
+        for (const [key, value] of Array.from(headers.entries())
+            .sort((a, b) => a[0].localeCompare(b[0])))
+            res.setHeader(key, value);
+        res.writeHead(this.statusCode);
     }
 
     /**