BuiltWith - Find out the technology behind websites

VirusTotal - VirusTotal is a free service that analyzes suspicious files and URLs and facilitates the quick...

Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.

URLscan.io - urlscan.io is a free service to scan and analyse websites. When a URL is submitted to urlscan.io, an automated process will browse to the URL like a regular user and record the activity that this page navigation creates.

What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.

Hybrid-Analysis.com - Hybrid-Analysis.com is a free malware analysis service powered by payload-security.com.