Debugging (4.2 and Before)

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This section describes how to use the Microflow debugger in Mendix 4.2 and earlier. For the 4.3 and later guide, see Debugging


For a guide on how to set breakpoints, please refer to the 4.3 and later guide here

When a breakpoint is encountered during the execution of a microflow, the debugger will launch:

As you can see, the debugger is split into two panes. The left-hand pane displays the activities from the currently debugging microflow. The right-hand pane displays the variables that are currently in scope. Note that you can double-click on Entities, these will expand so that you can view the individual attributes. Whenever you click on a variable (or attribute), the current value will be displayed in the bottom right text area. The variables always display the current value, before the execution of the last microflow activity visible in the left pane.


  • By clicking the ‘Step’ button the microflow will execute the current activity and proceed to the next activity.
  • By clicking the ‘Run’ button the microflow will continue. If another breakpoint is encountered in the same microflow, the execution will break again.
  • If the current activity is either a nested loop or a microflow call, you can click the “Step into” button to debug that specific microflow. That activity will then expand, allowing you to step through that loop or microflow.

Keyboard Shorcuts

There are three keyboard shortcuts to match the buttons:

  • F6 maps to the ‘Step’ button.
  • F5 maps to the ‘Step into’ button.
  • F8 maps to the ‘Run’ button.