Freeside is an open source billing and account administration package for ISPs and Online Business. It is developed and distributed by Silicon Interactive Software Design (SISD). Freeside uses web interface that makes it simple to setup and to use.

Since it is a Web application, Freeside’s security options are extensive in nature. By turning off the Menu Option or by given a separate password, it is easy to protect different sections of the interface with different levels of access. Unlike the other billing packages, Freeside offers efficient integration with an ISP’s legacy systems.

Freeside is written in Perl and Uses Perl’s DBI that allows any database backend to store data. Freeside runs on any Unix platform and uses PostgreSQL or MySQL as the database. The number of people doing ISP billing is rising day by day. Freeside’s Unix-based nature is familiar to people who run Unix ISPs. Since Freeside is server-centric, deploying and using the software is easier for the people. It has the ability to import and export to a large variety of Unix servers.

The billing features of the software are enriched with flexible tax system supporting region-based taxes, different tax classes for different products, flexible pricing and rating plans, built-in session monitor. New pricing plans can be added easily to this software by Plug-in System.

Customizable HTML templates, online signups with real time credit card, self-service server are available along with its efficient web interface. Apart from these, Freeside API is available with to write own self-service pages or applications. Although Freeside is a free software, it is supported commercially with installation, customization, training and support services.