Systems don't come alone. In the modern world of microservices and cloud deployment, new components must interact with legacy systems, making integration an important key to success. Reactive Streams give us a technology-independent tool to let these heterogeneous systems communicate without overwhelming each other. The Alpakka project is an open source initiative to implement stream-aware, reactive, integration pipelines for Java and Scala. It is built on top of Akka Streams, and has been designed from the ground up to understand streaming natively and provide a DSL for reactive and stream-oriented programming, with built-in support for backpressure. Akka Streams is a Reactive Streams and JDK 9+ java.util.concurrent.Flow-compliant implementation and therefore fully interoperable with other implementations.