This is a guest post by Guillaume Laforge. Well known for his contribution to the Apache Groovy project, Guillaume is also the "Product Ninja and Advocate" of Restlet, a company focusing on Web APIs: with DHC (an API testing client), Restlet Studio (an API designer), APISpark (an API platform in the cloud), and the Restlet Framework open source project for developing APIs. Modern mobile apps, single-page web sites and applications, are more and...