These classes are for replacing NSNull objects from Arrays and Dictionaries when parsing API responses.
Download these files and add in your project.
import like this in your project:
#import "NSArray+NullReplacement.h"
#import "NSDictionary+NullReplacement.h"
NSDictionary *data=@{@"status":201,@"message":null};
data=[data dictionaryByReplacingNullsWithBlanks];
output will be
@{@"status":201,@"message":@""}
It will remove all Null objects and replace them with empty strings to avoid crashes in your app.