https://github.com/HackerNews/API
I'm not sure what rate limiting policy is in place, but in theory you can start with a request for maxitem and from that point on just GET all items down to zero until you hit some sort of blocker.
There's a dataset containing everything: bigquery-public-data.hacker_news.full
You can write SQL and is super fast. Sample:
SELECT * FROM bigquery-public-data.hacker_news.full LIMIT 1