1. Apparatus for establishing participant interfaces for transactions executed on a system including a network interface and a data processing resources which execute a transaction processes of the transactions according to a transaction processing architecture; comprising: programs of instructions executable by the system, stored on a medium accessible by the system, providing tools to build a definition of a participant interface for a participant in a particular transaction, the definition of a participant interface including a definition of an input document for the participant and a definition of an output document for the participant, the definitions of the input and output documents comprising respective machine-readable descriptions of sets of storage units and logical structures for the sets of storage units; and programs of instructions executable by the system, stored on a medium accessible by the system and responsive to the definitions of the input and output documents, to compile data structures corresponding to the sets of storage units and logical structures of the input and output documents compliant with the transaction processing architecture, to compile instructions executable by the system to translate the input document to the corresponding data structures, and to compile instructions executable by the system to translate output of the transaction processes into the sets of storage units and logical structures of the output document.