You can check against the API with just the first characters of your hashed password (SHA-1 or NTLM), for example: https://api.pwnedpasswords.com/range/21BD1 or you can download the entire dataset.
It's not a database, it's just files. And they are hosted by Cloudflare so they can cope with a lot of downloads.
I think he should make the files smaller my removing the second half of the hashes, i.e. reduce it from 40 hex digits to 20. This increases the change of a false positive (i.e. I enter my password, it says it was compromised but it wasn't, it just has the same hash as one that did) from 1 in 10^48 to 1 in 10^24 (per password), but that's still a huge number. (There's less than 10^10 people in the world, they only have a few passwords each). This will approximately halve the download, maybe more because the first half of each hash is more compressible (when sorted) the second half is totally random.
> You are being purposefully obtuse here. HIBP is a very, very well established site with a long history of operating in good faith.
Allowing people to query and someone downloading the entire dataset is normally considered abuse, so being blocked is the expectation here. You're so dense you're bending light around you.
I remember when I was searching the file for some passwords my friends and family use, it took me a while to work out that number too. There are some passwords that many people seem to independently come up with and think must be reasonably secure. I suppose they are to the most basic of attacks.
