Our Play frontends are entirely reactive/non-blocking, so yes, we're using the async features very heavily. We'll have a blog post about this in the near future

Our Play frontends are entirely reactive/non-blocking, so yes, we're using the async features very heavily. We'll have a blog post about this in the near future. Our Play backends, if they use JDBC to talk to a database, are fully blocking, since pretty much all JDBC drivers are blocking. One of the nice things about Play is it's easy to configure the thread pool to handle this configuration as well.