Right now RSS feeds are the closest thing to an officially endorsed “API” that we have. Unfortunately they only exist for individual users/organizations and collections.
The list of recent notebooks however has no such feed, making it impossible to retrieve a list of new notebooks without querying the unsupported, internal API.
The recently-published RSS feed is here:
https://api.observablehq.com/documents/public.rss
I think we’re just missing the meta tags to make it discoverable.
How heavily is the feed cached? Will it e.g. drop deleted notebooks and reflect changed titles?
It should be no more than thirty seconds out of date.
The feed no longer works. Accessing https://api.observablehq.com/documents/public.rss results in a HTTP 400 error and the response:
{"errors":[]}
To my knowledge this feed is currently the only index that contains all published notebooks. Any chance it can be restored?
I’m looking into it.
Thank you! 
This has been fixed.
Btw, what’s an acceptable request interval for RSS scraping?
Fun fact: Up until 2019-10-01 there are ~22400 published notebooks, the first being