Correct. There is presently no way to use the API for discovery of all assets and schemas for a given API key.

but Zapier is able to fetch base list by rest Api. as i saw on Zapier you can also check on www dot zapier dot com.

we also need this from your Airtable Api …

Indeed, and this suggests there is a sanctioned way to do this that is not shared openly. The Airtable API is fully open only to those vendors Airtable has chosen to be fully open with. More accurately, I think it’s simply an aspect of the integration work they had to do to make Airtable compatible with Zapier (and Integromat).

Perhaps soon this will change.