I'm about to create a bunch of web apps from scratch. (See http://50pop.com/code for overview.) I'd like for them to be able to be accessed from many different clients: front-end websites, smartphone apps, backend webservices, etc. So I really want a JSON REST API for each one.

Also, I prefer working on the back-end, so I daydream of me keeping my focus purely on the API, and hiring someone else to make the front-end UI, whether a website, iPhone, Android, or other app.

Please help me decide which approach I should take:

TOGETHER IN RAILS

Make a very standard Rails web-app. In the controller, do the respond_with switch, to serve either JSON or HTML. The JSON response is then my API.

Pro: Lots of precedent. Great standards & many examples of doing things this way.

Con: Don't necessarily want API to be same as web app. Don't like if/then respond_with switch approach. Mixing two very different things (UI + API).

REST SERVER + JAVASCRIPT-HEAVY CLIENT

Make a JSON-only REST API server. Use Backbone or Ember.js for client-side JavaScript to access API directly, displaying templates in browser.

Pro: I love the separation of API & client. Smart people say this is the way to go. Great in theory. Seems cutting-edge and exciting.

Con: Not much precedent. Not many examples of this done well. Public examples (twitter.com) feel sluggish & are even switching away from this approach.

REST SERVER + SERVER-SIDE HTML CLIENT

Make a JSON-only REST API server. Make a basic HTML website client, that accesses the REST API only. Less client-side JavaScript.

Pro: I love the separation of API & client. But serving plain HTML5 is quite foolproof & not clien

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