Use granite:include or cq:include within the dialog structureInside a dialog definition (e.g., cq:dialog/.content.xml)<myFieldjcr:primaryType="nt:unstructured"sling:resourceType="granite/ui/components/coral/foundation/include"path="/apps/your/components/basecomponent/cq:dialog/content/items/fields/f...

You can use AEM and write a sling model JSON exporter. DO not use servlet as it will have security concern over 3rd part app.