# What is AOL Server and ACS?

AOLserver is America Online’s Open-Source web server. Originally built by NaviSoft, before it was acquired by <span class="caps">AOL</span>, it is the backbone of one of the largest and busiest production environments in the world. AOLserver is a multithreaded, Tcl-enabled web server used for large scale, dynamic web sites. It was revised and released as open source in 1999. Phil Greenspun, the author of [Philip and Alex’s Guide to Web Publishing](http://philip.greenspun.com/panda/) strongly recommends <span class="caps">AOL</span> server and his company built their free [ArsDigita Community System](http://philip.greenspun.com/wtr/using-the-acs.html) on AOLserver.

  
OpenAcs is a tookit for building web Applications, which runs on the <span class="caps">AOL</span> Web Server.

- AOLServer: [https://aolserver.github.io/](https://aolserver.github.io/)
- OpenAcs: [http://Openacs.org](http://Openacs.org)
- Tcl: [http://aolserver.am.net/docs/3.0/tcldev.htm](http://aolserver.am.net/docs/3.0/tcldev.htm)
- [AOLserver Wikipedia page](https://en.wikipedia.org/wiki/AOLserver)