If you have nested JSON, then just call JSONObjectWithData
twice:
NSString *string = @"\"{ \\\"name\\\" : \\\"Bob\\\", \\\"age\\\" : 21 }\"";
// --> the string
// "{ \"name\" : \"Bob\", \"age\" : 21 }"
NSError *error;
NSString *outerJson = [NSJSONSerialization JSONObjectWithData:[string dataUsingEncoding:NSUTF8StringEncoding]
options:NSJSONReadingAllowFragments error:&error];
// --> the string
// { "name" : "Bob", "age" : 21 }
NSDictionary *innerJson = [NSJSONSerialization JSONObjectWithData:[outerJson dataUsingEncoding:NSUTF8StringEncoding]
options:0 error:&error];
// --> the dictionary
// { age = 21; name = Bob; }