The Open Architecture Community System (OpenACS) is an open-source web application framework licensed under the terms of the GNU GPL. The Open Architecture Community System provides:
- A set of applications, that can be used to deploy web sites that are strong on collaboration. Some of the applications are Workflow, CMS, Messaging, Bug/Issue tracker, e-commerce, blogger, chat and forums.
- A sophisticated application development toolkit, that provides an extensive set of APIs and services to enable quick development of new applications. Features include sophisticated permissioning, full internationalization, Ajax, form builder, object model, automated testing, subsites and a powerful package manager.
- OpenACS runs on AOLserver with either Oracle or PostgreSQL as its database.
Projects that are based on OpenACS include dotLrn, dotFolio, dotCommunity, dotConsult, and Project-Open. OpenACS was originally developed side-by-side with the ArsDigita Community System (ACS), a product of ArsDigita Corporation. ACS remains one of the more famous products to be based completely on AOLserver. In 2002, after the ACS code tree forked, the Tcl code base came to be maintained by the OpenACS project.