Unable to create customer, without password

[rital-naik-adrosonic]

Hi there, when I try to create customer with follwoing request:

 var customer = Customer()
                            customer.email = "test@mail.com
                            customer.firstName = "test"
                            customer.lastName = "test"
                            customer.username = "test test"

It returns "code=400, message=Bad Request"

But when I use

 var customer = Customer()
                            customer.email = "test@mail.com
                            customer.firstName = "test"
                            customer.lastName = "test"
                            customer.username = "test test"
                           customer.password = "Pass123"

above object, customer gets created succesfully. However I want to create a customer without passing a password. Please help.