The 10 Highest-Paid Tech Skills In 2016

6. Cassandra

Average annual salary in 2016: $123,459

Year-over-year change: Up 2.2 percent

Like Kafka, Cassandra is an open-source tool for big data supported by the Apache foundation. Apache says Cassandra is an option when a business needs scalability and high availability without hurting performance. It's also suitable for apps that can't afford to lose data, even when an entire data center goes down, the foundation says.