I was wondering this as well. It sounds like webflow does have plans in the future for an api, but I haven't heard anything recently.
I was playing around for a site for my mother in law and came up with a solution.
Using GoogleDocs and this api called sheetsu http://sheetsu.com you can basically use google docs as your database.
Here is my example: http://shairpin.webflow.io/pins/hair
the data here is created thru a form that submits to google docs:
I'm pretty excited about figuring this out the beta version of his api also allows you to replace data in the sheets programmatically via json and ajax.
I'll write up a tutorial later