A distributed transaction processing system is disclosed in which a process automation application receives a transaction request from a requesting application. In response to the request, the process automation application obtains a transaction definition for the transaction requested by the requesting application. This transaction definition comprises a plurality of operation definitions, which indicate a plurality of operations constituting the requested transaction. For each of the operation definitions in the transaction definition, the process automation application produces an operation request. These operation requests are sent to one or more service applications, and one or more responses are received by the process automation application after the operations are performed by the service applications. Based on the responses, the process automation application produces a transaction response, which is sent to the requesting application. In this manner, the requested transaction is completed.