User Agent Finder

User Agent Finder

A User Agent (UA) string is a piece of information that is sent by a web browser or other client software to identify itself to a web server. The User Agent string typically includes details about the software, device, and operating system being used to access a website or web service. It allows websites to tailor their content and functionality based on the characteristics of the user's device and browser.

The User Agent string is part of the HTTP header that is sent by the client when making a request to a web server.  It is a string of text that typically follows a pattern like:

Mozilla/<version> (<system-information>) <platform> (<platform-details>) <extensions>

It contains information such as:

• Browser Name and Version: Indicates the name and version of the web browser (e.g., Chrome, Firefox, Safari, Internet Explorer).
• Operating System: Specifies the operating system on which the browser is running (e.g., Windows, macOS, Android, iOS).
• Device Information: In some cases, the User Agent string may include information about the device (e.g., desktop, mobile, tablet).
• Rendering Engine: The underlying engine that the browser uses to render web pages (Gecko for Firefox, WebKit for Safari).

Here are a few examples of User Agent strings:

Chrome on Windows:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

• Browser: Chrome
• Operating System: Windows 10 (64-bit)
• Rendering Engine: AppleWebKit/537.36
• Version: Chrome/119.0.0.0
• Compatibility Note: The User Agent includes references to Mozilla and Safari for compatibility reasons

Chrome on iPhone:

Mozilla/5.0 (iPhone; CPU iPhone OS 16_7 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/119.0.6045.109 Mobile/15E148 Safari/604.1

• Browser: Chrome (CriOS indicates Chrome on iOS)
• Device: iPhone
• Operating System: iOS 16.7
• Rendering Engine: AppleWebKit/605.1.15
• Version: Chrome/119.0.6045.109

Chrome on iPad:

Mozilla/5.0 (iPad; CPU OS 15_8 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/119.0.6045.109 Mobile/15E148 Safari/604.1

• Browser: Chrome (CriOS indicates Chrome on iOS)
• Device: iPad
• Operating System: iOS 15.8
• Rendering Engine: AppleWebKit/605.1.15
• Version: Chrome/119.0.6045.109

Edge on Windows:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36 Edg/119.0.0.0

• Browser: Edge
• Operating System: Windows 10 (64-bit)
• Rendering Engine: AppleWebKit/537.36
• Version: Edg/119.0.0.0 (Edge version based on Chromium)

Firefox on Windows:

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/119.0

• Browser: Firefox
• Operating System: Windows 10 (64-bit)
• Rendering Engine: Gecko/20100101
• Version: Firefox/119.0

Safari on iPad:

Mozilla/5.0 (iPad; CPU OS 15_8 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.6.6 Mobile/15E148 Safari/604.1

• Browser: Safari
• Device: iPad
• Operating System: iOS 15.8
• Rendering Engine: AppleWebKit/605.1.15
• Version: Version/15.6.6

Safari on iPhone:

Mozilla/5.0 (iPhone; CPU iPhone OS 16_7_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Mobile/15E148 Safari/604.1

• Browser: Safari
• Device: iPhone
• Operating System: iOS 16.7.2
• Rendering Engine: AppleWebKit/605.1.15
• Version: Version/16.6

User Agent strings can be obtained using server-side scripts on a website or by using JavaScript on the client side. Additionally, web browsers often provide developer tools that allow users to inspect network requests, where the User Agent string is usually visible.

Website developers can use the information from the User Agent string to optimize the user experience for specific browsers or devices. For example, they might deliver different style sheets or functionality based on whether the user is on a mobile or desktop device, or they might provide alternative content for users of specific browsers.

It's worth noting that while the User Agent string can provide useful information, it can also be manipulated or spoofed by users or browser extensions, so a solution solely  relying on this information may not be fully reliable.

For example, cURL (“Client for URLs”) has a default user agent string that may look like this:

curl/8.0.1

However, cURL allows  a custom string to be supplied by using the “-A” or “--user-agent” options.

Example:

curl -A ”I am R2-D2” http://www.example.com/