From the Spray Website:
Fully asynchronous, non-blocking
All APIs are fully asynchronous, blocking code is avoided wherever at all
Actor- and Future-based
spray fully embraces the programming model of the platform it is built upon.
Akka Actors and Futures are key constructs of its APIs.
Especially sprays low-level components are carefully crafted for excellent
performance in high-load environments.
All dependencies are very carefully managed, sprays codebase itself is kept
as lean as possible.
Being structured into a set of integrated but loosely coupled components your
application only needs to depend onto the parts that are actually used.
All spray components are structured in a way that allows for easy and