# Assigning a site's user

## Passing a `partner_user_id`

This is the unique user ID you use for this user internally (i.e. their login to your system or a customer ID). If you provide a `partner_user_id` in the params, you don't need to include `user_id` in your request.

In addition to supplying `partner_user_id`, unless you are certain that a User account has been created already on our side, you will need to also pass the user's details to us. These are `first_name`, `last_name`, and `email`. These fields are used to automatically create a User account on our side if it does not already exist. If you are not sure if a user account is already created for the supplied `partner_user_id`, then you can always pass these values to maintain consistency.

### Example of the `partner_user_id` param being used

```javascript
{
  "subdomain": "www"
  "domain": "somebusinessname.com",
  ...

  "partner_user_id": 12345,
  "first_name": "John",
  "last_name": "Doe",
  "email": "john.doe@gmail.com"
}
```