Domain Registrar with API for bulk lookup

Hi out there,

I'm looking for a project of mine for a domain registrar that has an API that allows bulk (>10'000) lookup of domain names.
I'm already registered at several registrars, but all off them state in their TOS that bulk lookups are not allowed, and I don't want to get banned for overdoing it.

I'm talking about looking up 4 times a day a list of around 10'000-100'000 domains.

Anybody has a hint for me?

Are you checking a list of potentially expired domains? You can try doing Whois lookups or even just plain CURL requests.

thanks @rafark

yeah it goes in this direction. I know about the Whois, RDAP and DNS approach.

Whois is not giving away expired information for every TLD,
RDAP is about to replace/extend Whois, but seems also to miss sometimes expired information (and is yet a pain to use)
and DNS is also only an indicator.

I'm using DNS and Whois in my approach, but to be sure I need the bulk lookup.