config.json

{
  "map": {
    "projection": "EPSG:900913",
    "units": "m",
    "center": {"x": 8.880386352539062, "y": 44.44897735945844, "crs": "EPSG:4326"},
    "zoom":12,
    "maxExtent": [
      -20037508.34, -20037508.34,
      20037508.34, 20037508.34
    ],
    "layers": [{
      "type": "osm",
      "title": "Open Street Map",
      "name": "mapnik",
      "source": "osm",
      "group": "background",
      "visibility": true
    },
    {
      "format": "image/jpeg",
      "name": "rv:rv1",
      "params": {},
      "singleTile": false,
      "title": "e-Geos Ortofoto RealVista 1.0",
      "type": "wms",
      "url": "http://www.realvista.it/reflector/open/service",
      "visibility": false
    },
    {
      "type": "tileprovider",
      "title": "OpenTopoMap",
      "provider": "OpenTopoMap",
      "name": "OpenTopoMap",
      "source": "OpenTopoMap",
      "group": "background",
      "visibility": false
    }]
  }
}