"Mergence is a high performance, open source HL7integration engine and application platform. It was developed to fill the need for an open source, fully transactional healthcare integration system capable of handling millions of messages per day, and thousands of concurrent LLP connections. Mergence is based on Apache ServiceMix, a lightweight enterprise service bus which conforms to the JBI standard, and HAPI, an excellent opensource HL7v2 API. We plan to support HL7v3 in the next release."
Please note that this Website is not maintained any longer and contains probably outdated information. You are still welcome to use it if it is of any help.