The API is documented here: https://fediseer.com/api/

Expanding models :: InstanceDetails gives a useful description of the attributes and their data types, but nothing about how to fetch the whole DB. Is there a nightly ZIP or tarball, or a way to get the dump in JSON?

I tried this:

curl -o fediseer.json 'https://fediseer.com/api/v1/all_instances'

It seems hung for a long time then produces a small file with just:

<html><body><h1>504 Gateway Time-out</h1>
The server didn't respond in time.
</body></html>

update

Nevermind, it works… Must’ve been a temporary outtage/glitch.