SymmetricDS - SymmetricDS is an asynchronous database replication software package that supports multiple subscribers and bi-directional synchronization.
Apache Camel - Apache Camel is a versatile open-source integration framework based on known enterprise integration patterns.
Kettle Pentaho - Pentaho Data Integration ( ETL ) a.k.a Kettle
Apache Kafka - Apache Kafka is an open-source message broker project developed by the Apache Software Foundation written in Scala.
CData Sync - Straightforward data synchronizing between on-premise and cloud data sources with a wide range of traditional and emerging databases.
elastic.io - elastic.io connects your SaaS to other cloud apps in seconds.