BuiltWith - Find out the technology behind websites
Amio Messaging SDK - Develop for multiple messengers using JavaScript
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Slack RTM API - Slack's Real Time Messaging API
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Location SMS - Location SMS is an application that allows the users to locate themselves by sending a simple text ‘Where are you?’ to the phone.