{"id":"381f05c5-b02e-4aa1-8def-c54a6026764a","feature":"Feature1","settings":{"dateFilter":"Today","startDate":1547701200000,"endDate":1547701200000}}

{"id":"0cf1378a-3a38-491e-9a22-926140a2a562","feature":"Feature2","settings":{"objectId":"addfg1231ds"}}

String payload = '{"id": ...}';
Map<String, Object> data = (Map<String, Object>)JSON.deserializeUntyped(payload);