A voice interaction development tool is described. Initially, user input associating voice interaction data with a visual object is received via a user interface. The voice interaction data, for example, may include voice commands and corresponding output content. Subsequently, a request is received from a voice assistant platform, due to initiation via a voice command to the voice assistant platform. In real-time (e.g., as the user speaks the voice command) a visual object corresponding to the spoken voice command is graphically indicated, e.g., a flow diagram element corresponding to the voice command is emphasized. In real-time as output content corresponding to the voice command is output by a voice assistant device, the user interface provides a graphical indication of the visual object associated with the output content. In this way, the described system provides graphical feedback for testing voice interactions being developed.