Please let me share μcuREST library which is aimed for easy creation of RESTful and/or JSON-RPC API in IoT projects.
The concept of this library is described on this page. In short words - you define a map of URIs to application’s variables/functions and μcuREST makes them accessible via HTTP protocol.
The ZIP with the library sources packaged for Spark Particle SDK is available for downloading from GitHub. Just unzip in in the SDK’s top directory and it will create user/libraries/micurest with the library sources, user/applications/micurest_snip and user/applications/micurest_demo with a simple example and more advanced demo application. The demo is also available as prebuilt binary on this link.
Library sources are hosted on GitHub as well https://github.com/hutorny/micurest
Below you may find some screenshots made from the demo application.