Plack - PSGI reference implementations and utilities
What are PSGI and Plack?
PSGI is a specification of gateway interface protocol between Perl web applications and web servers, like Python's WSGI and Ruby's Rack. See PSGI specification and FAQ for details.
Plack contains reference implementations of PSGI servers and also has useful utility tools like Plackup (command line server and application launcher), Plack::Util (Useful utilities for server implementors) and Plack::Builder (DSL to quickly enable and configure Plack middleware in .psgi file).