Proteus is described as 'End-to-end project management solution developed for the energy and engineering consulting industries, helping teams meet project demands across the full lifecycle, from proposal development to project delivery' and is a CRM system in the office & productivity category. There are more than 100 alternatives to Proteus for a variety of platforms, including Web-based, Windows, Mac, Linux and Android apps. The best Proteus alternative is Odoo, which is both free and Open Source. Other great apps like Proteus are ERPNext, Dolibarr, Bitrix24 and EspoCRM .