@Steve Strassmann Thanks for this question! The Line Resource in the Document Content Resource (JSON) has a textAreas property where you should see your line labels.

Below is an example of how this should appear, I hope it’s helpful! If you’re not seeing your line labels as textAreas in your JSON, please share your line resource and documentID so we can troubleshoot. 

Example

I created a similar diagram as your example (screenshot) and exported to JSON.

To illustrate this example, the items from the JSON export of this doc are pasted below:

"items": {
                "shapes":  
                    {
                        "id": "RIkvBWKNEYBA",
                        "class": "TerminatorBlockV2",
                        "textAreas":  
                            {
                                "label": "Text",
                                "text": "Terminator shape (3)"
                            }
                        ],
                        "customData":  ],
                        "linkedData":  ]
                    },
                    {
                        "id": "yIkvrMCZd5LZ",
                        "class": "DecisionBlock",
                        "textAreas":  
                            {
                                "label": "Text",
                                "text": "Decision shape (1)"
                            }
                        ],
                        "customData":  ],
                        "linkedData":  ]
                    },
                    {
                        "id": "MIkvNIz8uAn-",
                        "class": "TerminatorBlockV2",
                        "textAreas":  
                            {
                                "label": "Text",
                                "text": "Terminator shape (2)"
                            }
                        ],
                        "customData":  ],
                        "linkedData":  ]
                    }
                ],
                "lines":  
                    {
                        "id": "jJkvjg01cOo7",
                        "endpoint1": {
                            "style": "None",
                            "connectedTo": "yIkvrMCZd5LZ"
                        },
                        "endpoint2": {
                            "style": "Arrow",
                            "connectedTo": "MIkvNIz8uAn-"
                        },
                        "textAreas":  
                            {
                                "label": "Text",
                                "text": "Yes (line 1)"
                            }
                        ],
                        "customData":  ],
                        "linkedData":  ]
                    },
                    {
                        "id": "fJkvjlEl.8~S",
                        "endpoint1": {
                            "style": "None",
                            "connectedTo": "yIkvrMCZd5LZ"
                        },
                        "endpoint2": {
                            "style": "Arrow",
                            "connectedTo": "RIkvBWKNEYBA"
                        },
                        "textAreas":  
                            {
                                "label": "Text",
                                "text": "No (line 2)"
                            }
                        ],
                        "customData":  ],
                        "linkedData":  ]
                    }
                ],
                "groups":  ],
                "layers":  ]
            },

To determine line connections using shape IDs from the JSON, you can map which lines are connected to which shapes using the shape id property.

• For each line in the lines list, you would take note of the connectedTo value of both endpoint1 and endpoint2.
• This connectedTo value should match the id of one of the shapes in the shapes list.

For this example:

• Line with ID jJkvjg01cOo7 has endpoint1 connected to shape with ID yIkvrMCZd5LZ (Decision shape 1) and endpoint2 connected to shape with ID MIkvNIz8uAn- (Terminator shape 2).
• Line with ID fJkvjlEl.8~S has endpoint1 connected to shape with ID yIkvrMCZd5LZ (Decision shape 1) and endpoint2 connected to shape with ID RIkvBWKNEYBA (Terminator shape 3).

OK got it, thanks!