https://www.gerritcodereview.com/
Gerrit ( GERR-it) is a free, web-based team code collaboration tool. Software developers in a team can review each other's modifications on their source code using a Web browser and approve or reject those changes. It integrates closely with Git, a distributed version control system.
Gerrit is a fork of Rietveld, a code review tool for Subversion. Both are namesakes of Dutch designer Gerrit Rietveld.