Code Collaborator is described as 'Learn more about CodeCollaborator, the industry's first code review tool. Download this lightweight yet robust tool and try it free'. There are five alternatives to Code Collaborator for a variety of platforms, including Windows, Linux, Online / Web-based, Self-Hosted solutions and Docker. The best alternative is Upsource, which is free. Other great apps like Code Collaborator are Review Board (Free, Open Source), Crucible (Paid), Review Assistant (Paid) and LightReview (Free).
Review Board is a web-based collaborative code review tool, available as free software under the MIT License. Review Board can be installed on any server running Apache or lighttpd and is free for both personal and commercial use.
Review Assistant is a code review plugin for Visual Studio. The code review tool allows creating review requests and responding to them without leaving Visual Studio. Review Assistant supports TFS, Subversion, Git, Mercurial, and Perforce.