HTML::Mason is a Perl-based web site development and delivery system. Its main features include:

Components written in the Mason syntax are translated to pure Perl code and cached. The optimal usage scenario of HTML::Mason is to load it in a mod_perl environment within an Apache web server. This way, compiled Perl code stays in memory and is reloaded only when the source is changed. HTML::Mason is highly customizable and is distributed freely as open source. You can get it at CPAN.

The Mason's website is at http://www.masonhq.com.

The alternative systems, with slightly different functionality and philosophy, are HTML::EP, HTML::Embperl, eperl.