[etaque]

You might want to give a try to Prismic.io (for backend UI) + backed.js (for static generation, consumes Prismic API):

https://prismic.io/ https://github.com/prismicio/baked.js

disclaimer: I work at the company backing the project, although not on this product.

[eloisant]

BTW Prismic.io can also be used with Metalsmith: https://github.com/mbanting/metalsmith-prismic