Is it possible change username in Amazon Cognito with iOS SDK?

Question

as written in the title is it possible change username of a Amazon Cognito user? I can't find anything in documentation

Answer 1

It is possible to update the preferred_username of a Cognito User using the iOS SDK, using the updateAttributes API call. However, kindly note that you would not be able to modify the username of a user. Quoting the official AWS documentation,

The username value is a separate attribute and not the same as the name attribute. A username is always required to register a user, and it cannot be changed after a user is created.

But, the preferred_username value can indeed be changed, and a sample code to change the preferred username using the iOS SDK, as per the official documentation is stated as follows:

AWSCognitoIdentityUserAttributeType * attribute = [AWSCognitoIdentityUserAttributeType new];
attribute.name = @"preferred_username";
attribute.value = @"John User";
[[user updateAttributes:@[attribute]] continueWithSuccessBlock:^id _Nullable(AWSTask<AWSCognitoIdentityUserUpdateAttributesResponse *> * _Nonnull task) {
    //success
    return nil;
}];

I would also like to state that the AWS API documentations for the iOS SDK are rather minimal, and I would recommend developers to go through the SDK source code whenever in doubt.