If we request data from the Content API (Umbraco 13) , is this the same as requested the data via a webpage? I've been out the loop of Umbraco for a bit, the cache used to be called nuCache. So what i'm asking is does the content API get it's data from nuCache (or the new equivalent) or is it directly calling the Database? Many thanks

If you're talking about the Content Delivery API, then yes, the data comes from Examine.