NanoHttpd is a lightweight HTTP server designed for embedding in other applications. It's only one Java file, in two "flavors", one strictly Java 1.1 compatible, and one at "current" standards. It supports GET, POST, PUT, HEAD and DELETE requests, and supports file uploading with very small memory overhead. Temp file usage and the threading model are easily customized.
Higgs.IO is a high performance, message oriented network library built for realtime systems. It provides a core extensible framework and libraries built on top of the core. Libraries include a WebSocket server, an HTTP server and client, and Boson, a custom serialization and RMI library.
Kangee is a personal on-demand fileserver that makes it possible to send files to your friends. Dragging a file into the Kangee window will generate a link, which can be sent to your friend, who may open it in a Web browser and download the file. It also supports an "Add Upload" feature, which generates a link that lets your friends send files to you. It uses UPnP, STUN, and a connection test Web service to set up incoming connections, and can generate QR codes from the links to uploads and downloads.
QtWebApp allows you to write standalone Web server applications in C++ as easily as Java Servlets. The HTTP 1.1 server supports persistent connections, sessions with cookies, and file uploads. It contains a template engine and a logger that can be configured at runtime. The application runs on Unix as a daemon, on Windows as a service, and on all operating systems on the command line. It is based on Nokia QT 4.7. Compatibility with QT 4.8 and 5.0 has been verified successfully.
Zbatery is an HTTP server for Rack applications on systems that either do not support fork(), or have no memory (nor need) to run the master/worker model. It is based on Rainbows! (which is based on Unicorn (which is based on Mongrel)) and inherits parts of each. Zbatery supports your choice of all the thread/fiber/event/actor-based concurrency models and Rack middleware that Rainbows! supports (or will ever support) in a single process. Zbatery will still exploit certain features of Unix for transparent upgrades, log reopening, and graceful stops, but does not rely on them for basic functionality.
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.
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.