The diagram
Every HTTP response is a decision.
Send a request from the rail, or call this page's live URL with curl, and watch the flowchart decide the status one question at a time.
WebMacha sandbox
The very first question in the diagram is whether the service is up at all. B13 says false, so nothing else is asked and the answer is 503.
Decision flow
Decision path
Send a request to see its path through the machine.
Request log
No requests yet. Simulated and live requests appear here; select one to replay it.