For a webMethods messaging trigger that receives documents from Universal Messaging, the Execution user property indicates which credentials Integration Server should use when invoking services associated with the trigger. When a client invokes a service via an HTTP request, Integration Server checks the credentials and user group membership of the client against the Execute ACL assigned to the service. Integration Server performs this check to make sure that the client is allowed to invoke that service. When a webMethods messaging trigger executes, however, Integration Server invokes the service when it receives a message rather than as a result of a client request. Integration Server does not associate user credentials with a message. You can specify which credentials Integration Server should supply when invoking a webMethods messaging trigger service after receiving a document from Universal Messaging by setting the Execution user property for the trigger.

You can instruct Integration Server to invoke a service using the credentials of one of the predefined user accounts (Administrator, Default, Developer, Replicator). You can also specify a user account that you or another server administrator defined. When webMethods messaging trigger receives a message from Universal Messaging, Integration Server uses the credentials for the specified user account to invoke the service specified in the trigger condition.