You're right that there are too many requests being made. We're fixing this very soon, stay tuned.
Thanks for your feedback - we're in a early private beta and your inputs are very valuable to us.
Is there a particularly nice layer of abstraction that HTML5stac provides?
The demo app does in fact using Backbone+Bootstrap.
What HTML5stac makes dead simple for you is mapping your backend data models to Backbone Collections. In addition, we have responsive images, and adaptive templates, built into the framework.
Here's the error in the console: Failed to load resource: the server responded with a status of 429 (UNKNOWN STATUS CODE) GET https://apiv2.mobstac.com/api/2.0/accounts/1/properties/1/ap...
IMO responsiveness is a broad approach, and it doesn't necessarily imply only a pure CSS3 approach using media queries. If using JavaScript can make the web app more "responsive" to user needs, what's wrong with that?