BuiltWith - Find out the technology behind websites
LinkedIn Recruiter - LinkedIn Recruiter is a recruiting tool to hire talent from LinkedIn.
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Lever - A modern web app for hiring. Lever is a simple, powerful way to manage lists of candidates during the hiring process.
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Greenhouse - Greenhouse Software makes companies great at hiring.