Gitweb is a Git web interface. It is written in Perl and can be used as a CGI script, or as a mod_perl legacy script.
License: Open Source
Kallithea is a more feature-rich platform supporting multiple version control systems with tools for code review, while Gitweb is a lightweight, simple tool focused solely on Git repositories. Kallithea offers more customization and flexibility, whereas Gitweb is easier to set up and use for basic Git repository management.