Use Rails 5 Release Candidate. Rails has everything you need to develop a web service &#x2F; API for a mobile app.<p>Also, there is a new API-only mode in Rails 5 which could come in handy for your case (API development): <a href="http:&#x2F;&#x2F;edgeguides.rubyonrails.org&#x2F;api_app.html" rel="nofollow">http:&#x2F;&#x2F;edgeguides.rubyonrails.org&#x2F;api_app.html</a>