Adding Maps inside Map<dynamic, dynamic > Dart/Flutter Update: my code: Map<dynamic, dynamic> theSnapShot; theSnapShot = { ‘map1’: { ‘-LyUAD8B0LpKZ-5-cRn-‘: { ‘CoordsMap’: [null, {‘FirstCoords’: ‘30.088,31.279’,}] } } }; Map<dynamic, dynamic> masterMap; masterMap. addAll(Map.