The Tutoring Service is a stand-alone server program that provides tutoring to desktop applications and web clients. Of the various tutor types that can be created with CTAT, the Tutoring Service supports Example-tracing tutors created with Flash.

In contrast to the traditional CTAT architecture where student interface, tutoring engine, and supporting files are all stored on a single computer, the Tutoring Service architecture is more distributed: the Tutoring Service, running on a server, has access to supporting files (such as behavior graphs), and provides tutoring information over a network to a student interface (itself typically hosted on another computer).

The results of this distribution are that behavior graph reading and processing occurs entirely in Java on the server running the Tutoring Service, increasing graph loading speed. The behavior graph (a large XML file) is never sent to the client—only light-weight tutoring messages are sent to and from the Tutoring Service. These messages can be logged on the server hosting the Tutoring Service, or sent to a logging service that stores and processes them.

The Tutoring Service takes its name from the way that tutoring is communicated (i.e., through a TCP socket). It shares most of its code with the main CTAT application, but lacks a user interface. Although it acts a server, it does not provide web server functionality.

The Tutoring Service is included with the CTAT installation starting with version 2.0.