Unreal Engine Bridge

A minimal Chrome extension that lets hosted HTTP(S) pages proxy requests to a local Unreal Engine 5 Remote Control HTTP API running on http://127.0.0.1:30010.

Why this exists

Browsers do not allow remote websites to directly call your local Unreal Engine Remote Control endpoint on localhost. Unreal Engine Bridge solves that by:

1. injecting a content script into HTTP(S) pages,
2. forwarding page messages to the extension service worker,
3. proxying approved local HTTP requests to Unreal Engine, and
4. returning the response back to the page.

Examples

The hosted demo page is available at examples/index.html.

• Chrome extension: examples/unreal-engine-bridge.zip
• Use cases: manual QA, bridge verification, and a starting point for your own hosted Unreal tools

Features

• Bypass browser CORS and Private Network Access (PNA) restrictions when accessing the UE5 Remote Control API from a web page
• Call Unreal Engine Blueprint-exposed functions and Console Commands from a web page
• Run Unreal Engine Python scripts from a web page for automation, tooling, and content workflows
• Combine the fast iteration speed of web tools with Unreal Engine's powerful game creation capabilities
• Get started quickly with the hosted demo page in examples/index.html and the extension package in examples/unreal-engine-bridge.zip
• Learn more advanced Remote Control workflows in the official Unreal Engine documentation

Installation

Install from Chrome Webstore

this extension has published to Chrome Webstore: https://chromewebstore.google.com/detail/unreal-engine-bridge/oofjaldaobmdaeelhikfipjibmfniedi

Load unpacked extension from source

1. Open chrome://extensions
2. Enable Developer mode
3. Click Load unpacked
4. Select the src/ folder in this repository

Chrome requires manifest.json to be at the root of the selected folder, so when developing locally you should load src/, not the repository root.

Install from zip

1. Unzip examples/unreal-engine-bridge.zip
2. Open chrome://extensions
3. Enable Developer mode
4. Click Load unpacked
5. Select the extracted unreal-engine-bridge folder

Unreal Engine requirements

Before using the bridge, enable the Remote Control API plugin in Unreal Engine.

Then make sure Unreal Engine exposes the Remote Control HTTP API locally:

• Base URL: http://127.0.0.1:30010
• Protocol: HTTP
• Allowed hosts: 127.0.0.1, localhost
• Allowed port: 30010

Unreal settings

For the bridge and the example page to work reliably, configure the following Unreal settings.

RemoteControlSettings

bRestrictServerAccess=True
bEnableRemotePythonExecution=True

Optional for screenshot flows only:

bAllowConsoleCommandRemoteExecution=True

EditorPerformanceSettings

bThrottleCPUWhenNotForeground=False

These settings are important because:

• bRestrictServerAccess=True keeps the Remote Control server limited to local access.
• bEnableRemotePythonExecution=True is required by screenshot and other Python-driven helper flows used by examples/index.html.
• bAllowConsoleCommandRemoteExecution=True is only needed for flows that trigger Unreal console commands, such as the screenshot example that calls HighResShot.
• bThrottleCPUWhenNotForeground=False helps avoid background-editor throttling when Chrome and Unreal are open side by side.

If your Unreal instance uses a different port, update both:

• src/manifest.json host permissions
• the validation logic in src/background.js
• any calling page such as examples/index.html

Quick start

1. Start Unreal Engine with Remote Control HTTP API enabled on 127.0.0.1:30010
2. Install the extension in Chrome
3. Host or open an HTTP(S) page that speaks the bridge protocol
4. Open examples/index.html from a local web server or copy its bridge logic into your own tool page
5. Call UE_BRIDGE_PING to confirm the extension is available
6. Call UE_LOCAL_FETCH to proxy local requests through the extension

Important: Chrome extensions do not run on file:// pages in this setup. Use an HTTP(S) page.

Security model

src/background.js intentionally keeps the proxy narrow:

• only http:// URLs are allowed
• only 127.0.0.1 and localhost are allowed
• only port 30010 is allowed
• unsupported message types are rejected

This prevents arbitrary cross-network proxying from remote pages.

Development

Because this project is plain JavaScript, there is no build step.

After editing src/manifest.json, src/background.js, or src/content.js:

1. go to chrome://extensions
2. find Unreal Engine Bridge
3. click Reload
4. refresh your tool page

Rebuild the zip package

From the repository root:

mkdir -p examples
rm -f examples/unreal-engine-bridge.zip
tmpdir=$(mktemp -d)
mkdir -p "$tmpdir/unreal-engine-bridge"
cp src/manifest.json src/background.js src/content.js "$tmpdir/unreal-engine-bridge/"
(cd "$tmpdir" && zip -rq /path/to/this/repo/examples/unreal-engine-bridge.zip unreal-engine-bridge)
rm -rf "$tmpdir"

This keeps the repository source under src/ while producing a release zip whose extracted folder has manifest.json at the root, which is what Chrome expects.