User-agent explanation

Md. Mahim Bin Firoj
2 min readSep 4, 2023


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

We often encounter the above type user-agent string from there we need to find out what is the browser of the source from where the requests are coming.

image source:

Let’s breakdown each part:

Mozilla/5.0 — This part is a common token that indicates the user agent is compatible with Mozilla browsers.

(Windows NT 10.0; Win64; x64) — The source using a windows 10, 64-bit architecture.

AppleWebKit/537.36 (KHTML, like Gecko) — This is the browser rendering engine. Google chrome and safari both use this same engine. Firefox use Gecko engine. Rendering engine is used for visualize the web page contents to you.

Chrome/ Safari/537.36You need to know this part. Now the question is how we become sure that what browser the source is using as both the browser use applewebkit engine for rendering!!! The answer is chrome/ because it takes precedence over safari. is the chrome browser version number.

Likewise safari is the browser and 537.36 is the browser version.

Another one:

Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko

  • Mozilla/5.0: This part of the User-Agent string is common to many web browsers and indicates that the browser is compatible with Mozilla (which was one of the first web browsers).
  • (Windows NT 6.1; WOW64): This section specifies the operating system. In this case, it's Windows NT 6.1, which corresponds to Windows 7. The "WOW64" part indicates that it's a 64-bit version of Windows running on a 64-bit processor.
  • Trident/7.0: Trident is the layout engine used by Internet Explorer. This part of the User-Agent string indicates that it's using version 7.0 of the Trident engine.
  • rv:11.0: This section specifies the rendering engine version. "rv" stands for "revision," and it's set to 11.0, which corresponds to Internet Explorer 11.
  • like Gecko: The "like Gecko" part is often included to inform websites that the browser's rendering behavior is similar to that of the Gecko engine used by browsers like Mozilla Firefox. It's used for compatibility.

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