Wordpress
Not recommended. They have “headless” API capabilities, but those are slow, not reliable, and not supported.
ApostropheCMS
Both online-service and self-hosted. More for marketing site markup than repeating data.
Looks great. It seems to cater to freelance web developers who need a CMS for their clients. Features in-place editing, where someone can log into a website and edit the content right there where it is displayed. Like the better PHP systems, but in JavaScript. Very nice.