A Web services registry is arguably one of the most important components of SOA. The registry provides a single source of information about all services in an enterprise.
There are a number of commercial registry/repository products but all of them are quite pricey. Also, smaller organizations or organizations just starting with SOA may not need the full power of a commercial registry/repository product; most of it functionality will remain unutilized. On the other hand, existing registries do not do a particularly good job of managing dependencies between services as well as between service consumers and service providers. Dependency management must be a key consideration in SOA since, unlike in the case of monolithic applications, an SOA consists of a large number of “moving parts”, that is, services. In a well developed SOA most services depend on other services and these services in turn may rely on some other services. Being able to manage and analyze services dependencies is required in order to be able to implement robust and maintainable SOA.