The API is based on Bulk Whois API: https://bulk-whois-api.com/documentation/
The Mashape endpoint uses Synchronous mode and supports only Query API call, but it is possible to use multiple queries in parallel.
To use Mashape endpoint, you are required to use the Mashape authentication, not the one described in the original documentation.
The requests done to Mashape endpoint contain query argument, which must be either a domain without subdomains or IPv4 address. A definition of domain without subdomains differs across TLDs. For simple TLDs such as .com, .biz, .info, etc. a valid query must consist of a second level domain and a top level domain (e.g. example.com). For some TLDs, however, the second level domains are reserved and a valid domain name without subdomain includes a third level domain too - e.g. example.co.uk.
The format of responses and errors are equivalent to the original API.