A content compiler is a program that translates a document (not required to be XML) to a non-XML format, such as PDF, PostScript or HTML Help. Unlike content pipelines, which have a uniform interface, each content compiler is configured and invoked in a different way. Two content compilers are built into Arbortext Editor — the PTC Arbortext Formatting Engine and the PTC Advanced Print Publisher. Other content compilers are separate binaries that run under the control of Arbortext Editor. Others are programs supplied and licensed by third parties.

Content compilers are invoked by the publishing framework after the content pipeline finishes running. This post-process callback is explained in The Outer Layer of the Publishing Framework.