Rationale
We wanted our services to be reusable, composable and shareable across all our applications. They should be as easy to access from a daemon as from client side script. They should have standardized auth and security — and finally: the services that make up our applications should also actually be the public api. The web app should just be one of the api-consuming clients, not privileged in any way compared to an iPhone or Android native client.
We call services that adhere to this informal standard pebbles.
More joy, more leisure
In the year since we started building our applications from stacks of pebbles, we have noticed a dramatic increase in velocity and productivity, and decrease in maintenance work. We get more done and get more (and better) sleep.
So far pebbles has been an internal, closed source effort — but friends don't let friends build their businesses on proprietary software, so we always knew this would have to go open source at some point. That's basically the purpose of this site.