A web developer is a programmer who specializes in, or is specifically engaged in, the development of World Wide Web applications, or distributed network applications that are run over HTTP from a web server to a web browser.

Web Developer is an extension for Mozilla-based web browsers that adds editing and debugging tools for web developers. It has been tested to be compatible with Firefox, Flock, and Seamonkey. The extension was developed by Chris Pederick, who has also authored the User Agent Switcher extension.