Currently I'm developing the back-end of a PHP application using Recess Framework. I'm almost done and I now need to do the front-end. I have many alternatives and I prefer a CMS. The alternatives in my knowledge are Drupal or Wordpress. The problem is that I've never used Drupal and Wordpress(or any better). Thus I don't which one to choose to develop the app to interact with the REST interface.Can you help me in choosing the best CMS for interacting with the REST interface
A typical CMS has tightly coupled back end and front end code (unfortunately). Tightly coupled means that it would be a complete waste of time to try and separate the two.
What you can do is:
The hard part is the database. Every CMS is built to work with a very specific database structure and your back end will have to adopt that structure if you want to glue it with the CMS front end. In this scenario there is no real benefit in choosing Wordpress over Drupal (or vice versa or any other CMS, like Joomla), simply because the challenges of the scenario have nothing to do with the CMS itself. Whichever one you choose, you'll have to either:
If your website is a typical website, and all your needs are covered by the CMS backend (and/or some plugins) then the scenario you're proposing doesn't make any sense. You should just stick with the CMS.
If your needs exceed what the CMS can offer you, and you've made sure that there isn't a plugin out there that does what you want, then the sane choice to still be able to use the CMS, would be to convert your code into a plugin for the CMS of your choice. Or you could just code the front end from scratch as you did with the back end.
I won't go into the which CMS question, since none actually makes sense. I'd advice you to evaluate all three major CMS for PHP, Wordpress, Joomla and Drupal and decide for yourself. CMSes are extremely easy to work with, and relatively easy to code for. I strongly believe that every PHP developer should be familiar if not fluent in all three major CMSes (plus a few more), as to always be able to choose the right one for the job at hand.
Kudos for choosing Recess, it's a great framework, better built than a lot of more popular frameworks.