Monitoring messages during execution of a message flow

The present invention relates to monitoring program execution and the effects of program execution in a visual programming environment. Provided are an execution monitoring tool, a method and a computer program product for monitoring a message processing program or system. The execution monitoring tool identifies locations within the message processing program corresponding to a predefined set of execution progress stages, and inserts execution progress report generator components at these locations. Execution progress reports (including a representation of the message contents and structure) are then sent to the execution monitoring controller which maps the report data to its own representation of the program to determine the current position within an execution program. The message contents and structure, as well as the structure of the program and the current execution position, are displayed during execution on a test system. The execution reports include the current execution status as well as the position within the execution flow.