Embedthis Appweb is a fast, little embedded Web server. It is unmatched in efficiency and serves pages at native speed, using an event-driven, non-blocking core to serve multiple requests using minimal resources. It has integrated caching and the Embedded Server Pages C-Language Web framework. Without compromising performance, it has extensive security controls and a rigorous security sandbox that helps protect the server and mitigate denial-of-service attacks. It is one of the most widely deployed embedded Web servers and is used in networking equipment, telephony, mobile devices, industrial control, and consumer and office equipment, and in high-performance Web services.
GNU libmicrohttpd is a small C library for embedding HTTP server functionality into other applications. It is reentrant, fast, supports HTTP 1.1, and permits listening on multiple ports. The API is simple and still powerful enough to allow programmers to use the entire HTTP feature set. SSL/TLS support is available as an option.
The CyaSSL embedded SSL library is a lightweight SSL library written in ANSI C and targeted for embedded and RTOS environments, primarily because of its small size, speed, and feature set. It is commonly used in standard operating environments and cloud services as well because of its royalty-free pricing and excellent cross platform support. CyaSSL supports industry standards up to the current TLS 1.2 and DTLS 1.2 levels, is up to 20 times smaller than OpenSSL, and offers progressive ciphers such as HC-128, RABBIT, and NTRU.
Unicorn is a Unix and LAN/localhost-optimized fork of the Mongrel HTTP server. It takes full advantage of functionality exclusive to Unix-like operating systems. It will reap and restart workers that die from broken apps, and there is no need to manage multiple processes yourself. Load balancing is done entirely by the operating system kernel. Requests never pile up behind a busy worker. The server does not care if your application is thread-safe or not, as workers all run within their own isolated address space and only serve one client at a time. All Rack applications are supported along with pre-Rack versions of Ruby on Rails via a Rack wrapper. It also supports atomic log cycling, nginx-style binary re-execution without losing connections, before_fork and after_fork hooks, and optional copy-on-write-friendly memory management.
lighttpd is a secure, fast, compliant, and very flexible Web server which has been optimized for high-performance environments. It has a very low memory footprint compared to other Web servers, and it takes care of CPU load. It has an advanced feature set that includes FastCGI (load balanced), CGI, Auth, Output-Compression, URL-Rewriting, SSL, and much more.
Alaya is a primitive chrooting Web server with basic WebDAV support. It can serve HTTPS and HTTP, and can authenticate using PAM, /etc/shadow, /etc/passwd, or using its own authentication files that allow for 'native' users that only have access to alaya content. It's intended to be a simple method of sharing content over WebDAV, and though it can be configured with a config file, it's easy to configure by command-line switches alone. Alaya always chroots to ensure that malicious users can't use '..' within a URL to access unintended documents, and that users can't accidentally leave documents in places outside of the chroot. It has a 'ChHome' mode that chroots users into their home directory and serves content from there. It supports .cgi scripts out of a trusted path (so not from within the chrooted WebDAV share) and read-only shared directories that are outside of the chroot (allowing access to shared content when in ChHome mode).
yaSSL is a C++ based SSL library for embedded and RTOS environments, designed for individuals who prefer to use the C++ language. For a C-based solution, please see CyaSSL. yaSSL supports the industry standards up to TLS 1.2, and also includes an OpenSSL compatibility interface.
Hiawatha is a secure and advanced Web server for Unix. It has been written with security as its main goal. It features advanced access control, prevention of SQL injection and cross-site scripting, banning of clients who try such exploits, the ability to run CGIs under any UID/GID you want, and many other features. These features make Hiawatha an interesting Web server for those who need more security than what the other available Web servers are offering. Hiawatha is also fast and easy to configure.