User-Agent Header Manager

Name: User-Agent Header Manager
Author: Viacheslav Zhabonos

Customize your browser's User-Agent and other HTTP headers with ease. This powerful extension lets you modify how websites see your browser, perfect for testing, development, and privacy customization.

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Features & Capabilities

User-Agent Header Manager

Features

Global & Per-Site Control

Set default headers that apply to all websites
Override headers for specific sites individually
Hierarchical configuration: global defaults with site-specific overrides

User-Agent Presets

Quick selection of popular browser User-Agents
Chrome, Firefox, Safari, Edge on Windows, macOS, and Linux
Mobile browsers: iOS Safari, Android Chrome
Search engine bots: Googlebot, Bingbot

Custom Headers

Modify any HTTP header beyond User-Agent
Accept-Language, Referer, Accept-Encoding, and more
Add custom headers for specialized testing

Flexible Targeting

Blacklist mode: Apply to all sites except ones you exclude
Whitelist mode: Only apply to specific sites you choose
Wildcard support: Use *.example.com patterns

Persistence

All settings saved automatically
Survives browser restarts
Import/Export settings for backup or sharing

Use Cases

Web Development: Test how your site responds to different browsers and devices
Privacy: Blend in with common User-Agents
Access Control: Access mobile or desktop versions of websites
SEO Testing: View your site as search engine crawlers
API Testing: Debug how servers respond to different headers
Compatibility Testing: Ensure your site works across browsers

How It Works

The extension intercepts HTTP requests and modifies headers before they leave your browser. Headers are applied in order of specificity: global headers serve as defaults, and site-specific configurations override them for particular domains.

Permissions

This extension requires access to all URLs to modify HTTP headers for any website you visit. All settings are stored locally in your browser - no data is sent to external servers.

Privacy

Your privacy is important. This extension:

Stores all data locally in your browser
Does not collect any personal information
Does not send data to external servers
Works completely offline after installation

User Growth & Download Statistics

Add-on

By:

Viacheslav Zhabonos

Daily users:

Version:

1.0.1 Last updated: 2026-02-23

Version code:

6158649

Creation date:

2026-02-17

Risk:

Permissions:

Size:

36.61KB

Email:

vy*****@gmail.com

Full description:

Source:

Firefox Add-ons Store

Data ingested on:

2026-06-03

Compare stats and ranking:

Ranking

# 111,661 ▲ 482

Other rankings

#111 in agent keyword 61 #220 in header keyword 40 ▼ 5

For Developers

Monetize with App Pass Boost with Extension Booster

Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.

Developed by:

Viacheslav Zhabonos

Firefox Add-ons Store

https://addons.mozilla.org/firefox/addon/user-agent-header-manager/

Email:

vy*****@gmail.com

Is User-Agent Header Manager Safe?

Risk impact

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

User-Agent Header Manager requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.

Risk impact analysis details

Critical Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
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Risk likelihood

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

User-Agent Header Manager may not be trust-worthy. Avoid installing if possible unless you really trust this publisher.

Risk likelihood analysis details

High This extension has low user count. Unpopular extensions may not be stable or safe.
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