Standard User Agent 🌐

Blend in flawlessly. No fingerprinting.

A lightweight browser extension that standardizes your User-Agent to the most common configuration, protecting your privacy by making you look exactly like everyone else.

Features

Seamless Spoofing

• Sets your User-Agent to the most standard, widely used Chromium configuration.
• Automatically adjusts between desktop (Windows) and mobile (Android) based on your device type.

Anti-Fingerprinting

• Updates the modern sec-ch-ua Client Hints HTTP headers dynamically on every request.
• Spoofs the navigator.userAgentData API accurately to ensure complex browser fingerprinting scripts see precisely the fake data instead of your real profile.
• Restores original navigator properties recursively like appVersion, platform, vendor, and oscpu.

Zero Performance Impact

• Uses highly optimized declarativeNetRequest for instant network-level manipulation without holding up pageloads.
• Injects required overrides into the page synchronously via pure isolated-world and main-world bridge scripting.

Manual Installation

Firefox:

1. Download or clone this repository
2. Go to about:debugging#/runtime/this-firefox
3. Click "Load Temporary Add-on"
4. Navigate into the Standard UA/ directory and select manifest.json

Chrome/Edge/Brave:

1. Download or clone this repository
2. Go to chrome://extensions/
3. Enable Developer mode
4. Click "Load unpacked" and select the Standard UA/ folder

Privacy

• Zero Tracking, analytics, or telemetry.
• No remote APIs accessed or servers communicating.
• Operates entirely offline using a statically analyzed popular UA string inline.
• Open Source and completely auditable.

How It Works

The extension operates on two levels:

1. Network Level: The background Service Worker configures declarativeNetRequest to intercept and dynamically overwrite network headers (User-Agent, sec-ch-ua, sec-ch-ua-mobile, sec-ch-ua-platform) and sets a custom internal Server-Timing header to pass configuration instantly.
2. Execution Environment Level: Content scripts intercept the Server-Timing headers even before the page’s code runs, modifying prototype chains to override Javascript APIs (navigator.userAgentData, navigator.userAgent) within both MAIN and ISOLATED worlds natively seamlessly.

License

Copyright 2026 TN3W

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.