1. One or more computer-readable media having thereon the following: a first plurality of web services APIs, each of which being for writing a distributed, message-passing application, wherein each of the first plurality of web services APIs are represented with a first common namespace prefix for logical grouping of the plurality of web services; and a second plurality of web services APIs, each of which being for writing a distributed message-passing application and having certain common characteristics that are not present in all of the first plurality of web services APIs, wherein each of the second plurality of web services APIs are represented having both the first common namespace prefix and a second common namespace prefix that is a sub-namespace of the first common namespace prefix.