Perlbal is a Perl-based reverse proxy load balancer and web server. Perlbal is maintained by a group connected to Danga Interactive. The program is in common use by large web sites to distribute the load over a number of servers.Like Perl, Perlbal is distributed under both the GNU General Public License and the Artistic License and is thus free software.Perlbal also features a so-called "re-proxy" mechanism.