Code Compare is a free compare tool designed to compare and merge differing files and folders. Code Compare integrates with all popular source control systems: TFS, SVN, Git, Mercurial, and Perforce. Code Compare is shipped both as a standalone file diff tool and a Visual Studio extension.
Beyond Compare - Beyond Compare allows you to compare files and folders.
SonarQube - SonarQube, a core component of the Sonar solution, is an open source, self-managed tool that systematically helps developers and organizations deliver Clean Code.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Codacy - Automatically reviews code style, security, duplication, complexity, and coverage on every change while tracking code quality throughout your sprints.
Araxis Merge - Home of the award-winning Araxis Merge two and three-way file comparison (diff) and merging application, Araxis Find Duplicate Files, Araxis Replace In Files, and the Araxis Ketura issue tracking, project scheduling and time tracking application.
CodeClimate - Code Climate provides automated code review for your apps, letting you fix quality and security issues before they hit production. We check every commit, branch and pull request for changes in quality and potential vulnerabilities.