Soa + Restful Api

In my web application, front-end only use RESTful API to exhcange JSON data with back-end. The back-end is in Yii.

There are 3 plans, 1) free, 2)small biz, 3)corporate. There 3 plans has different features and UI. (check out the attachment)

My question is

1)how do I implement the 3 plans feature on SOA + RESTful architecture? Is should it be done through API, or at the back-end?

  1. What should be the db structure for this 3 plan features? How it works at database level?

Sincerely,

Thank you!

Nicolas