Yes, there is a difference when creating identities with usernames "VN001abc" and "VN001abC" in Ory Kratos, but it depends on how these usernames are used. For password credentials, Ory Kratos lowercases all password identifiers. This means that if you're using these usernames as password identifiers, "VN001abc" would be treated the same as "VN001abC" during authentication. As stated in the documentation: > It's important to understand that Ory Identities lowercases all

password

identifiers and therefore email addresses. > -

userNAME

is equal to

username

[Customize identity schemas](https://www.ory.sh/docs/kratos/manage-identities/customize-identity-schema#choosing-between-username-email-and-phone-number) However, the original case is preserved in the identity traits themselves. So if you're using these usernames for display purposes or other non-authentication functions, the case difference would be maintained in the stored identity. When creating custom identity schemas with usernames as identifiers, you would define them in your schema like this:

json {   "properties": {     "traits": {       "properties": {         "username": {           "type": "string",           "<http://ory.sh/kratos|ory.sh/kratos>": {             "credentials": {               "password": {                 "identifier": true               }             }           }         }       }     }   } }

This configuration would allow users to log in with their username, but the authentication process would treat "VN001abc" and "VN001abC" as identical for login purposes.