Interchange is a free and open source e-commerce web application server and platform written in Perl. Its primary use is building customized e-commerce and catalog solutions.

It is a descendant of Vend, an e-commerce system originally developed by Andrew Wilcox in early 1995. Mike Heins took the first publicly-released version, Vend 0.2, and added searching and DBM catalog storage to create MiniVend. Mike released MiniVend 0.2m7 on December 28, 1995. In 2000, ecommerce startup Akopia acquired Mike's consultancy, Internet Robotics, hired him, and merged its product, Tallyman, with MiniVend, to create Interchange. (Tallyman was a GPL'd web framework written in Perl and Embperl, backed by Oracle or PostgreSQL.)

In 2001, Akopia was acquired by Red Hat. Within a few years, Red Hat had tightened its focus on Enterprise Linux and ended its involvement with Interchange, which is now maintained by its community of developers, including ex-Akopia employees, most of whom still make a living doing Interchange development.

Source: Wikipedia