WSO2 provides open source middleware products including the WSO2 Enterprise Service Bus (ESB) and WSO2 Registry. The ESB provides capabilities for connecting, transforming, and managing integrations between services. It is based on Apache Synapse and adds features like a management console and integration with the WSO2 Registry. The Registry provides a centralized storage for resources with versioning, permissions, and lifecycle management capabilities. It can be used locally or as a shared registry in a cluster. Both products are modular and customizable using the Carbon OSGi architecture.