The Enterprise OSGi specification provides a compelling programming model for creating modular, portable, and dynamic enterprise applications. The Apache Aries project is an open source implementation of this standard. It is designed to complement existing web servers with a new set of pluggable enterprise-level services such as transactions, persistence, service bindings, and dependency injection. The Blueprint container standardizes the popular Spring component model, enabling dependency injection, application component assembly, and allowing beans to be easily swapped in and out for unit testing. Integration with JPA and JNDI standards allow declarative persistence and interoperability with legacy applications. Support for transactions and JMX provide enterprise-level application control.