This parameter is required for all calls
This is your authentication token. All your requests must be authorized with your private token.
You will need a domain to get emails addresses as leads.
If you need to get more emails in one API call, you can optionally pass the
limit parameter to indicate the maximum number of emails returned.
Note: The default response will give you 10 emails. 1 credit is consumed every 10 or fewer emails per domain. For example, if you set your limit to 100 and it returned 100 emails, that single API request will consume 10 credits.