WSO2 is the ambitious two-year-old Sri Lanka start-up that’s writing a complete open source middleware platform for Web Services, funded by Intel Capital, which is expecting it to become the standard. Company CEO Sanjiva Weerawarana (pictured) says the company is building a platform that will compete on equal basis with the existing comprehensive SOA platforms on the market.

The second plank in this platform is an ultra-lightweight Enterprise Service Bus (ESB) that the company claims rewrites the rules for ESB design. It’s designed to simplify SOA implementation and usually ESBs are architected to support applications in an intranet with Web Services being at best an afterthought requiring another software layer.

Weerawarana was with IBM Research previously, and had a lot to do with IBM’s Web Services strategy, such as leading most of its WS-* initiatives. He says existing ESBs are jerry-built often using existing heavyweight stacks like J2EE, servlets and EJBs, which creates performance issues, complexity and conversion costs. He’s referring to things like BEA Aqualogic, Sonix ESB, IBM WESB, CapeClear ESB, ServiceMix, Mule and JBoss ESB.

So WSO2 rethought the ESB from scratch with Web Services in mind, beginning with a JVM and focused around an XML model. The result is supposed to be able to route messages with only sub-millisecond overhead – 10x less than other people’s – and scale to manage thousands of simultaneous connections.

It is also the first ESB to be based on the Apache Synapse 1.0 Web Service management and integration broker released at the same time. (WSO2 is very tight with Apache Web Services, providing the leading contributors.) The Apache Synapse project, an outgrowth of the Apache Incubator project, built a flexible, high-performance SOA framework around XML and Web Services.

WSO2’s ESB extended the Apache Synapse XML router and mediation engine with an integrated registry and simple graphical interface so administrators can connect, manage and transform Web Service interactions across their networks.

WSO2 says the ESB can instantly virtualize services; users can route, version, load balance, log, monitor, and manage services without changing their application code.

The company’s first priority, however, is interoperability, and so is designed to work with any XML, HTTP or JMS middleware, including .NET. It says it’s aiming at much wider integration than just Java.

To date, WSO2 has seen “hundreds of thousands” of free downloads of its initial product, an Apache Axis 2-based Web Services Application Server, and has collected 25 paying customers, including, it says, at least one Fortune 100. Intel provided the first $4 million in funding, which will see it through next year. It’s going to start casting about for another round by December. It’s got a few of years of work left to get through its product wish list.

WSO2 is looking ahead to a Mashup Server written in JavaScript this fall. It expects to have an external Web Services Registry this year and it’s working on Web Service management. Expected to follow are business rules, governance and policy, security and a portal all based on its Web Services Framework.