The messages sent here are about an Invoice that can be uniquely identified by the customer_id ("sartography") and a purchase order number (1001) It will fire a message connected to the invoice keys above, starting another process, which can communicate back to this specific process instance using the correct key. po_number customer_id po_number po_number customer_id customer_id Flow_10conab Flow_1qgz6p0 Flow_037vpjk Flow_1qgz6p0 the_topic = "first_conversation" Flow_02lw0q9 Flow_037vpjk Flow_10conab Flow_02lw0q9 { "customer_id": customer_id, "po_number": po_number, "amount": amount, "description": description, } the_payload