So if the method is social login, you can send a 400 (bad input) error back and that would redirect the user to the login page (with a generic message). You can create an issue about displaying a specific message (that can be read from the 400 error respose) and we can implement it very soon. If the method is email password, then you can send the following 200 response:

{
    status: "FIELD_ERROR",
    formFields: {
        id: "email",
        error: "This email is already in use via a social provider. Please sign in instead.
    }[]
}

> Also I think I will also have to add apis like auth/signup/email/exists? after disabling the default implementation Yea. You should actually! You can disable this by setting

disableDefaultImplementation

to

true

in the

signUpFeature

object. In this case, you will need to also implement the sign up API from emailpassword (copy / paste should work here again)