Domain Expiration Bot Help

Hi Im looking to make a Domain Expiration bot to tell me when a site I want is available for purchase. I have no idea where to get this data but Im sure its open to the public.
Where can I find it?

Thanks
*I dont want to use a service Im learning how to code so I want to do it myself.

you have to check whois data, expiration date included

Most TLD have a WHOIS API attached.
Some are free within a number of queries, some are cheap, some are expensive or limited.
Even some NIC providers have their own free API. But most API out there are scrapped from official WHOIS pages.
And some others just require access to the given API giving some documents