NaviServer[2][3] is a high performance web server written in C and Tcl.

It can be easily extended in either language to create web sites and services; there are over 35 modules available (including database integration or protocol support for UDP, SMTP, LDAP, DNS, COAP, etc.)

Recent new features include: NaviServer is based on AOLserver (version 4.10), AOL's open-source web server.

[5] It is different by supporting multiple protocols, providing higher scalability through asynchronous I/O and aims to be less conservative with new feature development.

Historically NaviServer was the original name of the server, a closed-source product by a company called NaviSoft in the early 1990s.