Scalability and load-balancing are key issues for Web services providers. As the market becomes more mature, the need for static pages on web sites decreases, and dynamic services become a must. These types of applications require increasing amounts of processing power.

One of our design goals has always been to make WSO2 SOA Enablement Server scalable and robust so that it can reliably support heavier networked server workloads. WSO2 SOA Enablement Server HTTP and HTTPS servers can serve a very large number of concurrent requests. This is done through multi-threading within a single WSO2 SOA Enablement Server instance or through multiple instances of WSO2 SOA Enablement Server listening on different ports or on different machines. To ensure reliability, limits can be set for message size and the number of concurrent requests each WSO2 SOA Enablement Server instance can handle.

WSO2 SOA Enablement Server uses a "stream-pull parser" and caches the schemata, connections, etc. This means WSO2 SOA Enablement Server is completely scalable against both the number of users and the size of the SOAP Message.