Checkout this simple todo app running on Google AppEngine. This is a work-in-progress sample app I’m working on to show at the next SproutCore Founders Meetup. The source code includes the SproutCore, a Google AppEngine backend and a Merb backend, with more to follow.

SproutCore applications are thick-clients, which means they download once to your web browser and run independently of the server. A lot of people naturally think this means that your server can run slow and it won’t matter. In some cases, this is true. More often, though, your application server actually needs to respond faster than it did before.

When you write a server-driven web app, the user constantly has to wait for the server to respond with some new HTML or Ajax between every few clicks. It’s slow and boring but at least it is consistently slow and boring.

When you switch to a SproutCore app, things speed up considerably for your users. Once your app is loaded, they can fly through the interface, selecting items, moving them around, deleting, creating, etc. The only time they have