What is a user agent string?

A user agent string is a short piece of text that a browser or application sends to web servers to identify itself. It typically contains the browser name and version, the operating system, and sometimes the device type. Servers use this information to tailor responses — for example, serving a mobile layout to phones or adjusting feature support for older browsers.

User agent strings follow no single strict standard, but most desktop and mobile browsers use a format that starts with Mozilla/5.0 for historical compatibility reasons. The string then lists the platform, rendering engine, and browser identity. Because any client can send any user agent string, they are easy to spoof and are commonly used in web testing, scraping, and privacy tools.

Tool description

This tool generates realistic random user agent strings for a wide range of browser and operating system combinations. You can filter by browser (Chrome, Firefox, Safari, Edge, Opera) and operating system (Windows, macOS, Linux, Android, iOS), and generate up to 50 strings at once. Version numbers reflect real release ranges to produce plausible output.

Examples

Chrome on Windows

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36

Firefox on Linux

Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:117.0) Gecko/20100101 Firefox/117.0

Safari on iOS

Mozilla/5.0 (iPhone; CPU iPhone OS 17_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 Mobile/15E148 Safari/604.1

Features

  • Covers Chrome, Firefox, Safari, Edge, and Opera across Windows, macOS, Linux, Android, and iOS
  • Generate up to 50 unique strings in a single click
  • Realistic version numbers drawn from actual browser release ranges