A system for providing document conversion services that uses XML (eXtensible Mark-up Language). A document type definition (DTD) defines tags and attributes for document conversion services, and includes a number of global variable definitions. Each "convertor" tag defines a document conversion filter, using a "filter" tag contained within it. Within each convertor tag, multiple input and output tags describe the capabilities of the convertor, and can be used to define the input document types and output document types for the associated filter. The filter tag can have a "class" attribute or the like, that may be used to provide a fully qualified class name for the filter. A "remote" tag defines whether the conversion for an associated filter is performed on an identified remote server computer system. The global variables are visible to all the convertor entities and may be used to activate logging of activities for various purposes.