WebSpeed is a framework within the OpenEdge product set that allows you to create web pages and Internet content from ABL.
An ABL executable is connected to a WebServer and the ABL programmer can get the HTTP requests, process them in ABL, and create an HTTP reply.
Typically this serves up HTML pages, but any Content-Type can be served up (CSS files, .js, images, json, xml, etc).
The programmer can write .p's that serve content "manually", but you can also embed ABL in HTML templates similar to java JSP's. (These are referred to as "SpeedScript" files). A third model called Object Mapping is also available, but seldom used recently.
The documentation for WebSpeed is part of the overall OpenEdge documentation set and is available with your OpenEdge install (and online in Progress Community)=