I had ~similar issue with Windows 10, Godot 4.0/4.2, Python 3.12, latest Chrome/Brave/Firefox and the local test server script from: https://github.com/godotengine/godot/blob/master/platform/web/serve.py.
I slightly modified the script and now it works for me.
Notice: you don’t tell anything about your environment, so this may or may not work for you. If it doesn’t seem to work right away, be sure to disable cache in browser’s dev tools and (force) refresh the game page.
# Script for running a local test server for Godot web exports
# Slightly modified from: https://github.com/godotengine/godot/blob/master/platform/web/serve.py
# Fixes issue with .js files getting wrong MIME type (Godot 4.2, Windows 10, Python 3.12)
from http.server import HTTPServer, SimpleHTTPRequestHandler, test # type: ignore
from pathlib import Path
import os
import sys
import argparse
import subprocess
class CORSRequestHandler(SimpleHTTPRequestHandler):
def end_headers(self):
self.send_header("Cross-Origin-Opener-Policy", "same-origin")
self.send_header("Cross-Origin-Embedder-Policy", "require-corp")
self.send_header("Access-Control-Allow-Origin", "*")
super().end_headers()
# IMPORTANT: without this .js files will have incorrect MIME type (text/plain) and the game won't work
CORSRequestHandler.extensions_map = {
# '.wasm': 'application/wasm',
".js": "text/javascript",
def shell_open(url):
if sys.platform == "win32":
os.startfile(url)
else:
opener = "open" if sys.platform == "darwin" else "xdg-open"
subprocess.call([opener, url])
def serve(root, port, run_browser):
os.chdir(root)
if run_browser:
# Open the served page in the user's default browser.
print(
"Opening the served URL in the default browser (use `--no-browser` or `-n` to disable this)."
shell_open(f"http://localhost:{port}")
test(CORSRequestHandler, HTTPServer, port=port)
if __name__ == "__main__":
parser = argparse.ArgumentParser()
parser.add_argument(
"-p", "--port", help="port to listen on", default=8060, type=int
parser.add_argument(
"-r",
"--root",
help="path to serve as root (relative to `platform/web/`)",
default=".",
type=Path,
browser_parser = parser.add_mutually_exclusive_group(required=False)
browser_parser.add_argument(
"-n",
"--no-browser",
help="don't open default web browser automatically",
dest="browser",
action="store_false",
parser.set_defaults(browser=True)
args = parser.parse_args()
# Change to the directory where the script is located,
# so that the script can be run from any location.
os.chdir(Path(__file__).resolve().parent)
serve(args.root, args.port, args.browser)
