There are several APIs online to check the WHOIS of a domain.
My first try was with Mashape's JsonWhoisAPI.com, but when it started having issues, I went looking for alternatives.

Here I have compiled three of the easiest to use.
The best I found was Jsonwhois.IO and the same team is also giving us WebCargo.IO. I also did it for JsonWhois.COM because it has a bigger number of free calls and it may be enough for some users. It is the only that requires the access token in the header of the request, all others take it as a parameter in the URL.

 In case you decide to expand this, one service I didn't liked was Hexillion.com. Few services, few trys and too eager to get credit card data. Also, it didn't work perfectly in OutSystems.


To read more, go to  my blog post