How do I run a local Unity WebGL (file:// url) build?

just open your terminal and go into your directory (where the HTML file lies), and start the server using one of the commands below.

python -m CGIHTTPServer 8360
python -m http.server --cgi 8360
python3 -m http.server --cgi 8360

This will open the port for you.

Then direct your browser to http://localhost:8360/YOURFILENAME.html The default one would usually be index.html ;)

The correct way to run your Unity-WebGL app locally is to use a simple server.

Even Unity itself runs as a small web server run you run a WebGL build from the editor.

Here's one, Here's another, here's a whole list others

Turning off your browser security is as poor advice as turning off your virus scanner or your firewall. Don't do it. Especially when the correct way is so trivial.

These instructions were found in Dr. Tim Chamillard's game development course:

Firefox (recommended browser for running WebGL)

1. Type about:config in the navigation bar
2. Search for the security.fileuri.strict_origin_policy parameter
3. Click that parameter to change it to false

Chrome

1. Add a shortcut to Chrome on your desktop if you don't have one
2. Right click the shortcut and select Properties
3. Select the Target text box, go to the end, add a space and add --allow-file-access-from-files
4. Double-click the index html file for the WebGL build and copy the URL in the navigation bar when the browser opens
5. Close the browser
6. Start the browser using the shortcut, paste in the URL you copied in Step 4 and press enter

Microsoft Edge

No need to do anything, WebGL builds work fine.

Safari

1. Enable the develop menu using the preferences panel, under Advanced → “Show develop menu in menu bar”
2. From the safari “Develop” menu, select “Disable local file restrictions”

As a general rule, restart your computer after making these changes since browsers require it and some don't.

I'm only adding this answer in case people don't want to deal with external tools, since Unity WebGL module already includes a web server. This works at least with the one shipped with Unity 2020.3.48f1 and later. If you have Unity and the WebGL module installed, the server file is located at

<editor install path>/Editor/Data/PlaybackEngines/WebGLSupport/BuildTools/SimpleWebServer.exe

You'll need to start CMD with admin privileges, and use 2 parameters: path_to_build and port

So for instance, let's say you move SimpleWebServer.exe to a new folder C:/Tools, and you keep your WebGL game build in C:/Builds/game_web, you could start the server using that admin cmd like this:

"C:/Tools/SimpleWebServer.exe" "C:/Builds/game_web" 8000

You should see something like this

Then you can navigate to http://localhost:8000/ in your browser to test your game.

If you're still facing issues, I recommend checking out this link: uusoft.itch.io/unity-webgl-local-hoster. It's an excellent free and open-source tool that might help you out with hosting Unity WebGL builds locally. Give it a try and see if it resolves your problem!

EDIT: This code appears to be written by the OP

This works with br files, you need node to run it

/* eslint-disable */
import path from "path";
import { fileURLToPath } from "url";

import express from "express";
import mime from "mime-types";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();

// Allow all CORS
app.use((req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Methods", "GET,PUT,POST,DELETE,OPTIONS");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  if (req.method === "OPTIONS") {
    return res.sendStatus(200);
  }
  next();
});
const unityDir = path.resolve(__dirname, "../public");

// Custom static middleware to handle .br files
app.get("/*", (req, res, next) => {
  const requestedPath = path.join(unityDir, req.path);
  if (requestedPath.endsWith(".br")) {
    res.setHeader("Content-Encoding", "br");
    if (requestedPath.endsWith(".wasm.br")) {
      res.type("application/wasm");
    } else {
      res.type(mime.lookup(requestedPath) || "application/octet-stream");
    }
  }
  next();
});

app.use(express.static(unityDir));

const PORT = process.env.PORT || 3001;
app.listen(PORT, () => {
  console.log(`S3 Simulator running at http://localhost:${PORT}`);
});

Then have a folder structure like

s3-simulator
|- index.js (this code)
public
|- unity
   |- Build

then open http://localhost:3001/unity/