diff --git a/README.md b/README.md
index 4cbb206..d4c86ff 100644
--- a/README.md
+++ b/README.md
@@ -29,10 +29,7 @@ router.cors()
 
 // Register global middleware
 router.use((req, res, next) => {
-  res.headers = {
-    ...res.headers,
-      'X-Global-Middlewares': 'true'
-  }
+  res.headers.set('X-Global-Middlewares', 'true')
   next()
 })
 
@@ -147,7 +144,7 @@ An unlimited number of functions getting [`req`](#req-object) and [`res`](#res-o
 Key       | Type                | Description
 --------- | ------------------- | -----------
 `body`    | `object` / `string` | Only available if method is `POST`, `PUT`, `PATCH` or `DELETE`. Contains either the received body string or a parsed object if valid JSON was sent.
-`headers` | `object`            | Object containing request headers
+`headers` | `Headers`           | Request [Headers Object](https://developer.mozilla.org/en-US/docs/Web/API/Headers)
 `method`  | `string`            | HTTP request method
 `params`  | `object`            | Object containing all parameters defined in the url string
 `query`   | `object`            | Object containing all query parameters
@@ -157,7 +154,7 @@ Key       | Type                | Description
 Key       | Type                | Description
 --------- | ------------------- | -----------
 `body`    | `object` / `string` | Either set an `object` (will be converted to JSON) or a string
-`headers` | `object`            | Object you can set response headers in
+`headers` | `Headers`           | Response [Headers Object](https://developer.mozilla.org/en-US/docs/Web/API/Headers)
 `status`  | `integer`           | Return status code (default: `204`)
 
 
diff --git a/index.d.ts b/index.d.ts
index 772030c..bd56b54 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -50,7 +50,7 @@ declare class Router {
      * @property {string} method HTTP request method
      * @property {Object<string, string>} params Object containing all parameters defined in the url string
      * @property {Object<string, string>} query Object containing all query parameters
-     * @property {Object<string, string>} headers Object containing request headers
+     * @property {Headers} headers Request headers object
      * @property {Object<string, string> | string} body Only available if method is `POST`, `PUT`, `PATCH` or `DELETE`. Contains either the received body string or a parsed object if valid JSON was sent.
      * @property {Object<string, string | number>} cf object containing custom Cloudflare properties. (https://developers.cloudflare.com/workers/examples/accessing-the-cloudflare-object)
      */
@@ -58,7 +58,7 @@ declare class Router {
      * Response Object
      *
      * @typedef RouterResponse
-     * @property {Object<string, string>} headers Object you can set response headers in
+     * @property {Headers} headers Response headers object
      * @property {number} status Return status code (default: `204`)
      * @property {Object<string, string> | string} body Either an `object` (will be converted to JSON) or a string
      * @property {Response} raw A response object that is to be returned, this will void all other res properties and return this as is.
@@ -306,7 +306,7 @@ type RouterResponse = {
     /**
      * Object you can set response headers in
      */
-    headers: Object<string, string>
+    headers: Headers
     /**
      * Return status code (default: `204`)
      */
diff --git a/index.js b/index.js
index 71ca66a..8454d75 100644
--- a/index.js
+++ b/index.js
@@ -54,7 +54,7 @@ class Router {
      * @property {string} method HTTP request method
      * @property {Object<string, string>} params Object containing all parameters defined in the url string
      * @property {Object<string, string>} query Object containing all query parameters
-     * @property {Object<string, string>} headers Object containing request headers
+     * @property {Headers} headers Request headers object
      * @property {Object<string, string> | string} body Only available if method is `POST`, `PUT`, `PATCH` or `DELETE`. Contains either the received body string or a parsed object if valid JSON was sent.
      * @property {Object<string, string | number>} cf object containing custom Cloudflare properties. (https://developers.cloudflare.com/workers/examples/accessing-the-cloudflare-object)
      */
@@ -63,7 +63,7 @@ class Router {
      * Response Object
      * 
      * @typedef RouterResponse
-     * @property {Object<string, string>} headers Object you can set response headers in
+     * @property {Headers} headers Response headers object
      * @property {number} status Return status code (default: `204`)
      * @property {Object<string, string> | string} body Either an `object` (will be converted to JSON) or a string
      * @property {Response} raw A response object that is to be returned, this will void all other res properties and return this as is.
@@ -80,8 +80,8 @@ class Router {
      * Handler Function
      * 
      * @callback RouterHandler
-     * @param {Request} request
-     * @param {Response} response
+     * @param {RouterRequest} request
+     * @param {RouterResponse} response
      * @param {RouterNext} next
      */
 
@@ -359,15 +359,12 @@ class Router {
                     status: 404
                 })
             }
-            const res = { headers: {} }
+            const res = { headers: new Headers() }
             if (Object.keys(this.corsConfig).length) {
-                res.headers = {
-                    ...res.headers,
-                    'Access-Control-Allow-Origin': this.corsConfig.allowOrigin,
-                    'Access-Control-Allow-Methods': this.corsConfig.allowMethods,
-                    'Access-Control-Allow-Headers': this.corsConfig.allowHeaders,
-                    'Access-Control-Max-Age': this.corsConfig.maxAge,
-                }
+                res.headers.set('Access-Control-Allow-Origin', this.corsConfig.allowOrigin)
+                res.headers.set('Access-Control-Allow-Methods', this.corsConfig.allowMethods)
+                res.headers.set('Access-Control-Allow-Headers', this.corsConfig.allowHeaders)
+                res.headers.set('Access-Control-Max-Age', this.corsConfig.maxAge)
             }
             const handlers = [...this.globalHandlers, ...route.handlers]
             let prevIndex = -1
@@ -380,8 +377,8 @@ class Router {
             }
             await runner(0)
             if (typeof res.body === 'object') {
-                if (!res.headers['Content-Type'])
-                    res.headers['Content-Type'] = 'application/json'
+                if (!res.headers.has('Content-Type'))
+                    res.headers.set('Content-Type', 'application/json')
                 res.body = JSON.stringify(res.body)
             }
             if (res.raw) {