User Agent Generator

User Agent Generator

Free online User Agent Generator. Create custom UA strings for Chrome, Firefox, Safari, Edge, bots & mobile devices instantly. No signup required.

Updated May 2026

CONFIGURATION
Browser
Operating System
Device Type

Ctrl+G to generate · Shift+Enter to copy

GENERATED OUTPUT
UTF-8

Click "Generate User Agent" to create a UA string

User Agent Generator Online — Free Custom UA String Builder

Generate any User Agent string in seconds. Whether you're building a web scraper, testing a REST API, simulating mobile devices, or debugging server-side behavior, this free User Agent Generator lets you create realistic, browser-accurate UA strings for Chrome, Firefox, Safari, Edge, and more — across every major OS and device type. No signup. No limits.

The tool supports bulk generation (Multi-Gen mode) for scraping pipelines that need to rotate UA strings, as well as bot UA strings for Googlebot and Bingbot. Every generated string matches the exact format used by real browsers in production.

How to Use the User Agent Generator

Getting a UA string takes about five seconds:

  1. Select a browser — Choose from Chrome (Latest or 110), Firefox (Latest or 115 ESR), Safari 17, Edge, Opera, Googlebot, or Bingbot.
  2. Choose an operating system — Windows 11/10, macOS Sonoma/Ventura, Linux, Android 14/13, or iOS 17/16.
  3. Pick the device type — Desktop, Mobile, or Tablet changes the platform token and mobile flag in the output.
  4. Click "Generate User Agent" — The string appears instantly in the terminal panel.
  5. Copy or download — One-click copy to clipboard or download as a .txt file for bulk use.

Use the Randomize button to get a random browser/OS/device combination instantly. Enable Multi-Gen to generate up to 50 unique UA strings at once for rotation pipelines.

What Is a User Agent String?

A User Agent (UA) is a short text string sent by a browser, bot, or HTTP client in the User-Agent request header. It identifies the software making the request — including the browser name, version, rendering engine, and operating system.

A typical Chrome UA string on Windows looks like:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Servers use this information to serve the right content format — for example, a mobile-optimized page for smartphones or a desktop layout for computers. In development, controlling the UA lets you test how your server responds to different clients without needing physical devices.

Common Use Cases

  • Web scraping: Rotating UA strings is one of the first techniques to bypass basic bot detection. By mimicking real browser UAs, scrapers avoid immediate blocks from sites that reject requests with generic or empty User-Agent headers.
  • API and backend testing: Some APIs return different responses depending on the client UA. Generating specific UAs lets you reproduce edge cases in staging without needing the actual device.
  • Mobile/device emulation: Simulating a mobile UA triggers mobile redirects and responsive behavior on servers that don't rely solely on CSS media queries.
  • SEO and crawler testing: Generating Googlebot or Bingbot UAs lets you see exactly what search engine crawlers fetch from your pages — useful for debugging rendering issues.
  • Automation pipelines (Selenium, Playwright, Puppeteer): Setting a custom UA string prevents headless browser fingerprinting by sites that block default Chromium headers.
  • Security research: Testing how authentication systems and WAFs respond to unusual or spoofed UA strings is a common reconnaissance step in authorized penetration tests.

Frequently Asked Questions

What is the format of a User Agent string?

A UA string follows a loose convention inherited from Netscape history. Most modern browser UAs start with Mozilla/5.0, followed by a platform token in parentheses (OS, CPU architecture), then the rendering engine identifier, and finally the browser-specific token. The exact structure varies by browser — Firefox uses Gecko/20100101 Firefox/X.Y, while Chrome-based browsers include AppleWebKit/537.36 (KHTML, like Gecko) Chrome/X.Y.Z.W.

Why do I need to generate a User Agent string?

Generated UA strings are most commonly used in web scraping (to mimic real browsers and reduce blocking), automated testing (to simulate responses for different device types), and API debugging. They are also used in CI pipelines to verify that server-side user agent detection logic works correctly before shipping to production.

Is using a fake User Agent legal?

In most jurisdictions, generating or sending a custom UA string is entirely legal — it's a standard HTTP request header, and servers do not require it to be accurate. However, using it to violate a website's Terms of Service, bypass paywalls, or access systems without authorization may be illegal depending on local laws. Always use this tool responsibly and only on systems you own or have permission to test.

What is the difference between a User Agent and a browser fingerprint?

A User Agent is just one component of a browser fingerprint. A complete fingerprint also includes screen resolution, installed fonts, timezone, WebGL renderer, Canvas API output, and audio characteristics. A matching UA alone does not make a request look like a genuine browser if the other fingerprint signals are missing or inconsistent.

How do I use a generated User Agent in Python?

Pass the string as a header in requests:

headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) ...'}
response = requests.get(url, headers=headers)

In Selenium, set it via ChromeOptions:

options.add_argument('--user-agent=Mozilla/5.0 (Windows NT 10.0; Win64; x64) ...')

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