JAM Stack == NO APIS @ Runtime?

I read on Jamstack's website that microservice backend APIs = more secure and better than monolithic. No examples of JAM stack show that it's calling microservice APIs at runtime (aka, on the CDN)

And if it's at deploy time, then that means all the APIs that it uses (unless 3rd party ones) can be private.

I think the JAM stack maybe mixing in ideas of dynamic content by throwing in the idea of microservice APIs to generate the static content when really, it may be more clear to focus on using APIs on deploy time only?

Please tell me if the above sounds crazy. I'm a noob to the #jamstack craze and want to make sure it's clear to me - and hopefully everyone ;)