Apache Rivet is an open source programming system that allows developers of web sites to use Tcl

Tcl

Tcl is a scripting language created by John Ousterhout. Originally "born out of frustration", according to the author, with programmers devising their own languages intended to be embedded into applications, Tcl gained acceptance on its own...

 as a scripting language for creating dynamic web sites. Rivet is similar to PHP

PHP

PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. For this purpose, PHP code is embedded into the HTML source document and interpreted by a web server with a PHP processor module, which generates the web page document...

, ASP

Active Server Pages

Active Server Pages , also known as Classic ASP or ASP Classic, was Microsoft's first server-side script engine for dynamically-generated Web pages. Initially released as an add-on to Internet Information Services via the Windows NT 4.0 Option Pack Active Server Pages (ASP), also known as Classic...

, and JSP

JavaServer Pages

JavaServer Pages is a Java technology that helps software developers serve dynamically generated web pages based on HTML, XML, or other document types...

. Rivet is primarily developed by Damon Courtney, David Welton, and Karl Lehenbauer

Karl Lehenbauer

Karl Lehenbauer was the founder of NeoSoft in the early 1990s, which was the first Internet Service Provider in the southern United States as well as the first to offer cable modem service in Houston, Texas, among other technological milestones. NeoSoft was later sold to Internet America in 1998...

.

Rivet can use any of the thousands of publicly available Tcl

Tcl

Tcl is a scripting language created by John Ousterhout. Originally "born out of frustration", according to the author, with programmers devising their own languages intended to be embedded into applications, Tcl gained acceptance on its own...

 packages that offer countless features such as database interaction (Oracle

Oracle database

The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....

, PostgreSQL

PostgreSQL

PostgreSQL, often simply Postgres, is an object-relational database management system available for many platforms including Linux, FreeBSD, Solaris, MS Windows and Mac OS X. It is released under the PostgreSQL License, which is an MIT-style license, and is thus free and open source software...

, MySQL

MySQL

MySQL officially, but also commonly "My Sequel") is a relational database management system that runs as a server providing multi-user access to a number of databases. It is named after developer Michael Widenius' daughter, My...

, etc.) or interfaces to popular applications such as the GD Graphics Library

GD Graphics Library

The GD Graphics Library is a graphics software library by Thomas Boutell and others for dynamically manipulating images. Its native programming language is ANSI C, but it has interfaces for many other programming languages. It can create GIFs, JPEGs, PNGs, and WBMPs...

.