A system and method for mediating a transaction of a digital document by converting a transaction into an internal representation according to predefined rules and according to processing definitions associated with the source of the transaction, validating and possibly altering the transaction in its internal representation according to predefined rules and according to processing definitions associated with the destination of the transaction, converting said internal representation into an external representation according to predefined rules and according to rules specific to a destination of said transaction and communicating the external representation to a destination.