The Frank!Framework is an easy-to-use, stateless integration framework which allows (transactional) messages to be modified and exchanged between different systems.

Apache Camel is an open source integration framework that empowers you to quickly and easily integrate various systems consuming or producing data.

Convert JSON from document-oriented DB to neo4j graph

Neo4j - Couchbase Connection API

AppNet is the next web service integration protocol. It connects web applications in an Android-like way and web services of any framework/protocol by a service broker system using OAuth2 based authorization. This is a speciifcation

A simple orchestration library for running complex processes or workflows in Java with visualization