Grav - The modern open source flat-file CMS
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Bludit - Bludit is a web application to build your own website or blog in seconds, it's completely free and open source. Markdown support.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
HTMLy - HTMLy is an open source databaseless blogging platform. A Flat-File Blog and Flat-File CMS written in PHP prioritizes simplicity and speed.
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs