In reply to Joshua.

The JSON API has been pushed back with no ETA on when it will be merged into WordPress core. They are doing there best to fix bugs, polish it up, and do a lot of testing. The API needs to be mostly right the first time.

You can start using the plugin and building stuff with it via https://wordpress.org/plugins/json-rest-api/ or for a more updated version, https://github.com/WP-API/WP-API