How do Wappalyzer detects technology of WebPage

Question

How do Wappalyzer detects back-end programming language of Site, but can't detect in some cases for eg: Facebook uses PHP but it can't detect and shows HTTP/2.

Answer 1

Wappalyzer is an open source community driven platform and all of it's source code can be found on this link: https://github.com/AliasIO/Wappalyzer

This is the specific file that does the detection https://github.com/AliasIO/wappalyzer/tree/master/src/technologies

In short, it uses regex on things like the site HTML, headers, scripts, meta, etc.

EDIT Jan 2021: The file containing the detection methods has changed to https://github.com/AliasIO/wappalyzer/blob/master/src/technologies.json Thanks @RaymondChenon for the update.

EDIT Nov 2021: The file(s) containing the detection methods has changed back to a folder with many files: https://github.com/AliasIO/wappalyzer/blob/master/src/technologies

Answer 2

As it has been mentioned. It uses regex to match what it already has. If facebook's php is not detected remember this.

• Facebook still uses PHP, but it has built a compiler for it so it can be turned into native code on its web servers, thus boosting performance.
• Facebook uses Linux, but has optimized it for its own purposes (especially in terms of network throughput). Exploring the software behind facebook

Also it's not easy to detect backend technologies if there is extensive use of API's that can be a chanllenge.

Wappalyzer also has a commandline version that I think works the same as the browser addon.

npm i -g wappalyzer 

That's what I think this folks are using for there Wappalyzer online