This may sound vaguely unethical, but it isn't so - I've been asked to make an app using data from a WordPress blog but I can't discuss adding a JSON API plugin through the admin panel right now. So I was wondering if there's a simple way to get all the posts from a blog with just their title, tags, and content.
As it turns out, there's an extremely simple way. As far as I can tell, however, this will only work for blogs hosted on wordpress.com itself. This doesn't require any authentication, but you'll only get public posts.
https://public-api.wordpress.com/rest/v1.1/sites/$sitename.wordpress.com/posts/
With $sitename being the site ID. This will elicit a fairly comprehensive JSON response that'll give you the title, content, tags, etc of all the public posts on the blog. Pretty cool, but very hard to find.