Config is described as 'SaaS tool for Configuration File Management created for Programmers, Sysadmins, and IT Managers. It is the easiest way to manage your config files across all your servers and environments'. There are more than 10 alternatives to Config for a variety of platforms, including Linux, Mac, Windows, BSD and Online / Web-based. The best alternative is DCImanager. It's not free, so if you're looking for a free alternative, you could try Ansible or Salt. Other great apps like Config are Puppet (Freemium, Open Source), Chef (Free, Open Source), Foreman (Free, Open Source) and Fabric (Free, Open Source).
DCImanager is a platform for managing physical equipment, which helps to optimize the use of computing power, improve the efficiency of the IT department, and flexibly transform the infrastructure according to business tasks.
Chef is an open source systems integration framework built to bring the benefits of configuration management to your entire infrastructure. You write source code to describe how you want each part of your infrastructure to be built, then apply those descriptions to your servers.
Rudder is an easy to use, web-driven, role-based solution for Continuous Automation and Compliance. Well established in companies from small to biggest-in-their-field. The biggest known deployment (2016) is about 7000 nodes.