🔍 /

User Agent String Generator

Generate valid, highly realistic User Agent strings for QA testing and web scraping. Features strict syntax compliance for modern browsers (Chrome, Safari, Firefox) and specific OS configurations (iOS, Android, Windows, macOS).

User Rating 0.0 ★★★★★
Total Usage 0 times
Category Dev Generators
My User Agent
SCANNING...
Scanning browser...
Generate Profile
Result
// Generated UA will appear here
Anatomy Analysis
Generate a string to see breakdown
Is this tool helpful?

Your feedback helps us improve.

★ ★ ★ ★ ★

About

User Agents (UAs) are the fundamental handshake of the modern web. Every HTTP request carries this string to identify the client's browser, operating system, and rendering engine version to the server. For QA engineers and full-stack developers, relying on a single UA during testing creates a massive blind spot.

Responsive logic often relies on regular expressions matching specific substrings like iPhone or Android 14 to serve mobile views. Security firewalls fingerprint these strings to distinguish real users from bots. This tool generates syntactically correct, modern strings ensuring your scraping scripts or responsive tests mimic real-world traffic accurately, bypassing naive bot detection and triggering the correct view logic.

qa-testing web-scraping browser-fingerprinting mock-data responsive-design

Formulas

A valid User Agent follows a strict legacy structure to maintain compatibility. The standard syntax breakdown is:

Mozilla/5.0 (system-info) Engine/ver (details) Browser/ver

Common Tokens Legend:

system-info ≡ Describes the OS and Architecture (e.g., Windows NT 10.0; Win64; x64).
Engine ≡ Rendering engine, usually AppleWebKit (Chrome/Safari) or Gecko (Firefox).
details ≡ Compatibility flags like KHTML, like Gecko.
Browser ≡ The actual browser identifier, e.g., Chrome/124.0.0.0 or Version/17.0.

Reference Data

Device / BrowserRisk FactorPattern / Syntax
Windows 10 / Chrome 124LOWMozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36
macOS 14 / Safari 17LOWMozilla/5.0 (Macintosh; Intel Mac OS X 14_4_1) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 Safari/605.1.15
iPhone 15 / SafariLOWMozilla/5.0 (iPhone; CPU iPhone OS 17_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Mobile/15E148 Safari/604.1
Android 14 / ChromeLOWMozilla/5.0 (Linux; Android 14; SM-S918B) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.6312.118 Mobile Safari/537.36
Generic Bot / CrawlerHIGHMozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
Linux / Firefox 125LOWMozilla/5.0 (X11; Linux x86_64; rv:125.0) Gecko/20100101 Firefox/125.0
Headless ChromeMEDMozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/124.0.0.0 Safari/537.36

Frequently Asked Questions

This is a historical artifact from the "Browser Wars". Early browsers checked for "Mozilla" to serve advanced features. To ensure compatibility, virtually all modern browsers (Chrome, Safari, Edge, Firefox) prepend "Mozilla/5.0" to claim they are compatible with the Mozilla rendering standard.
While using a realistic User Agent is the first step, modern anti-bot systems (like Cloudflare or Akamai) use TCP fingerprinting, TLS Handshakes, and JavaScript execution analysis. A correct string helps, but is not sufficient on its own against sophisticated protections.
On iOS, all browsers (including Chrome and Firefox) are forced by Apple policy to use the WebKit engine. A valid iOS User Agent for Chrome will say "CriOS" (Chrome for iOS) but still identify as AppleWebKit. Our generator handles these platform-specific nuances automatically.
Windows versions in UA strings rely on kernel version numbers. "Windows NT 10.0" corresponds to Windows 10 and Windows 11. "Windows NT 6.1" corresponds to Windows 7. "Windows NT 6.3" is Windows 8.1.