For MailChimp API 2.0 there was a method \'batch-subscribe\', to send in an array of email addresses to be added to a specific list in MailChimp.
How to implement this i
The page you're linking to look like docs from the beta, but either way, they say that batch operations aren't yet implemented. FWIW, the real docs also list Batch Operations as a part of the roadmap, so I doubt they're done yet.