Duration: 1995-ongoing

Contact Person: Univ.-Prof. Dr. Gustaf Neumann


OpenACS is a web application toolkit in a very crowded field of systems that purport to offer similar features. However, OpenACS offers a number of advantages over competing platforms.

Community in a Box

The OpenACS is a community system that is ready out-of-the-box for collaborative web sites. It provides functionality for discussions, content management, personalization and other mechanisms for users to communicate. In addition, the utilities available to extend this core functionality are easy to learn and to use.

Proven Architecture

The components of the OpenACS have proven themselves in the most demanding of applications. AOLserver is the backbone for AOL's most heavily trafficked sites. Both databases, Oracle and PostgreSQL, have likewise responded with excellent performance in demanding environments. And the OpenACS is in deployment at sites that have upwards of 40K users and is doing swimmingly.

Responsive Community

The OpenACS community is full of very professional and committed open-source developers. According to, OpenACS is one of the most active open source communities in the world. The forums on are well trafficked with discussions concerning OpenACS enhancements, solutions to bugs, and assistance to newbies, among other things. Help is offered and questions encouraged by gurus, wizards and the odd mortal programmer

Commercial Support

There are over a dozen companies dedicated to providing clients with OpenACS development and hosting. In addition to these companies, there are many independent consultants that are available for hire. This collection of commercial providers work together to maintain the OpenACS in addition to competing for clients. In fact, often times the vendors work together for the same client. Most importantly, no client is ever left without support, even if his or her original provider goes out of business.

Excellent Documentation

Unusual among open source projects, the OpenACS is very well documented. Community members are encouraged to document and distribute their new packages as well as address any lack of information in existing documentation.

Commitment of Heavy Hitters

Perhaps the most compelling reference for the OpenACS is the commitment of some very large and prestigious companies, institutions and non-governmental organizations. These include the MIT Sloan School of Management which has initiated and led the development of .LRN, an open-source courseware system build on OpenACS. Recently, the University of Heidelberg, the most prestigious German university, rolled .LRN out for their 40K users. In addition, the OpenACS was used to build the CMS for, a site that handles millions of hits per day.

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