Perlbal is a Perl-based reverse proxy load balancer and Web server. It processes hundreds of millions of requests a day just for LiveJournal, Vox, and TypePad, and dozens of other "Web 2.0" applications. One of the defining things about Perlbal is that almost everything can be configured or reconfigured on the fly without needing to restart the software.
MuleSoft Tcat Server is enterprise Tomcat made simple: a fully supported Tomcat server that allows developers to easily build and test today’s connected Web applications, and that simplifies Tomcat management and application provisioning tasks for administrators. Tcat Server has an easy graphical installer and headless installer for Linux (multi-distro: RHEL, Debian, CentOS, Fedora, Ubuntu, openSUSE, etc), Windows, Solaris 10, and Solaris 11. Tcat also offers reliable JVM restarts, server group deployments, a REST API for scripting the console in any language, a groovy shell built into the console, and JMX alerting and monitoring features.
G-WAN is an extremely fast Web application server. It runs scripts written in ANSI C. This server is safer than others, since it uses less code, no buffer copies, and no library calls that can lead to buffer overflows. G-WAN can outperform IBM Apache, Microsoft IIS, and Sun GlassFish by several orders of magnitude, both on Windows and Linux.
NXWEB is ultra-fast and super-lightweight web server for applications written in C. It can serve thousands of concurrent requests with a small memory footprint using an event-driven and multi-threaded model that is designed to scale. It features an exceptionally light code base, a simple API, decent HTTP protocol handling, keep-alive connections, SSL support (via GNUTLS), HTTP proxy (with keep-alive connection pooling), non-blocking sendfile support (with configurable small file memory cache), cacheable gzip content encoding, cacheable image thumbnails with watermarks (via ImageMagick), a modular design for developers, and the ability to run as a daemon.
mod_reserve is an Apache2 module for Linux that extends the Apache HTTP server, allowing it to reserve a certain CPU bandwidth for the provisioning of a service. This module exploits the functionality provided by AQuoSA, whose API is used to reserve CPU bandwidth for execution of tasks. In this way, the module can force the Web server to provide services, like CGI or Perl scripts, using exactly the configured CPU bandwidth. This behaviour is useful in order to provide Quality of Service to certain types of services, or to prevent the kinds of attacks in which a service can starve all the others.