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.
Dynamic Form is a Python request abstraction library that lets you write one request handler that will run on multiple Python Web frameworks (such as Django and Google's AppEngine). This allows you to create pages and apps once and use them on multiple projects without concern about which framework is being used. Additionally, it makes AJAX easy. Simply adding nested request classes allows you to define AJAX handlers that can easily be refreshed both sever-side and client-side.
GUI Builder is a drag and drop interface for creating WebElement User Interface (WUI) templates that can be used as the foundation of a responsive Wep app. It simplifies the process of designing applications, and encourages separation of the logic and view. It is part of the WebBot Web development framework, which makes it possible to build Web apps in a similar fashion to Qt/KDE apps.
ashttpd was originally a testbed for a kernel async-sendfile patch. Today, it's just another Web server for serving static content rapidly. It differs from its competitors by storing its webroot in a database, which provides a 50% performance increase over using the operating system's VFS. It also allows precalculation of strong cache-validators (ETags).
PySite is not a CMS in the traditional sense. Rather, you manage the contents of a Web site via a file manager interface, which gives you access to all settings (pages, styles, plugins, etc.). Compose your pages with Jinja templates, and edit your code comfortably with syntax highlighting in the ACE editor. You may write your stylesheets in Sass and let the integrated compiler write CSS files. PySite also contains a facility to manage virtual mailboxes, in case you maintain your own SMTP and IMAP server, e.g. with Postfix and Dovecot.
HTMTEX reads hand-coded ASCII HTML documents with embedded TEX-like islands (backslash-escaped symbols, inline math, and displayed math). It writes Unicode HTML documents with UTF-8 encoded symbols, and span- and table-formatted math. The converter itself is a customizable sed script. Visualization is regulated by a customizable stylesheet file.
phpsqlitesite is a minimal PHP/SQLite content Website system. It gives you a searchable multilingual site with automatic navigation and optional social sharing and comment sections. It consists of one PHP source code file and one SQLite database file, with no requirements other than PHP and SQLite.