diff --git a/src/DOM.js b/src/DOM.js
index 044d370676..b36bd078a6 100644
--- a/src/DOM.js
+++ b/src/DOM.js
@@ -12,7 +12,7 @@ const he = require('he');
 const parse5 = require('parse5');
 const parseIntStrict = require('parse-int');
 const selector = require('window-selector');
-const fetch = require('window-fetch');
+const fetch = require('./fetch');
 const {Blob} = fetch;
 const htmlUnescape = require('unescape');
 
diff --git a/src/Window.js b/src/Window.js
index 5198adc7be..cdaf5b1360 100644
--- a/src/Window.js
+++ b/src/Window.js
@@ -106,6 +106,7 @@ const {
 GlobalContext.id = id;
 GlobalContext.args = args;
 GlobalContext.version = version;
+GlobalContext.userAgent = `Mozilla/5.0 (OS) AppleWebKit/999.0 (KHTML, like Gecko) Chrome/999.0.0.0 Safari/999.0 Exokit/${GlobalContext.version}`;
 
 const {_parseDocument, _parseDocumentAst, getBoundDocumentElements, DocumentType, DOMImplementation, initDocument} = require('./Document');
 const {
@@ -493,7 +494,7 @@ const _makeRequestAnimationFrame = window => (fn, priority = 0) => {
     }
   }
   window.navigator = {
-    userAgent: `Mozilla/5.0 (OS) AppleWebKit/999.0 (KHTML, like Gecko) Chrome/999.0.0.0 Safari/999.0 Exokit/${GlobalContext.version}`,
+    userAgent: GlobalContext.userAgent,
     vendor: 'Exokit',
     platform: os.platform(),
     hardwareConcurrency: os.cpus().length,
diff --git a/src/WindowBase.js b/src/WindowBase.js
index 3b4037b1b5..b5901e09e5 100644
--- a/src/WindowBase.js
+++ b/src/WindowBase.js
@@ -20,7 +20,7 @@ const {
 const {CustomEvent, DragEvent, ErrorEvent, Event, EventTarget, KeyboardEvent, MessageEvent, MouseEvent, WheelEvent, PromiseRejectionEvent} = require('./Event');
 const {FileReader} = require('./File.js');
 const {XMLHttpRequest, FormData} = require('window-xhr');
-const fetch = require('window-fetch');
+const fetch = require('./fetch');
 const {Request, Response, Headers, Blob} = fetch;
 const WebSocket = require('ws/lib/websocket');
 
@@ -149,11 +149,6 @@ class Worker extends EventTarget {
   self.URL = URL;
 
   self.fetch = (u, options) => {
-    const o = Object.assign({}, options || {});
-    const h = (o.headers instanceof Headers) ? o.headers : new Headers(o.headers);
-    h.set('User-Agent', self.navigator.userAgent);
-    o.headers = h;
-    options = o;
     if (typeof u === 'string') {
       const blob = URL.lookupObjectURL(u);
       if (blob) {
diff --git a/src/Worker.js b/src/Worker.js
index 56b908af46..9fce9d3919 100644
--- a/src/Worker.js
+++ b/src/Worker.js
@@ -10,7 +10,7 @@ const {
 } = require('worker_threads');
 
 const {createImageBitmap} = require('./DOM.js');
-const fetch = require('window-fetch');
+const fetch = require('./fetch');
 const {XMLHttpRequest} = require('window-xhr');
 const WebSocket = require('ws/lib/websocket');
 const {FileReader} = require('./File.js');
diff --git a/src/core.js b/src/core.js
index d561b4182b..e3d74dd218 100644
--- a/src/core.js
+++ b/src/core.js
@@ -1,7 +1,7 @@
 const url = require('url');
 const {URL} = url;
 
-const fetch = require('window-fetch');
+const fetch = require('./fetch');
 const GlobalContext = require('./GlobalContext');
 const symbols = require('./symbols');
 const {_getBaseUrl} = require('./utils');
diff --git a/src/fetch.js b/src/fetch.js
new file mode 100644
index 0000000000..9e5558b469
--- /dev/null
+++ b/src/fetch.js
@@ -0,0 +1,13 @@
+const GlobalContext = require('./GlobalContext');
+const fetch = require('window-fetch');
+
+Object.assign(module.exports, fetch);
+
+module.exports = (u, options) => {
+  const o = Object.assign({}, options || {});
+  const h = (o.headers instanceof fetch.Headers) ? o.headers : new fetch.Headers(o.headers);
+  h.set('User-Agent', GlobalContext.userAgent);
+  o.headers = h;
+  return fetch(u, o);
+};
+
diff --git a/src/request.js b/src/request.js
index be37c72e7a..062251d185 100644
--- a/src/request.js
+++ b/src/request.js
@@ -17,7 +17,7 @@ consoleStream._writev = (chunks, callback) => {
 };
 global.console = new Console(consoleStream);
 
-const fetch = require('window-fetch');
+const fetch = require('./fetch');
 const {workerData, parentPort} = require('worker_threads');
 const {url, int32Array} = workerData;