Storm is a free and open source project licensed under the Eclipse Public License. The EPL is a very permissive license, allowing you to use Storm for either open source or proprietary purposes. Storm is hosted on GitHub.
Storm has a large and growing ecosystem of libraries and tools to use in conjunction with Storm. The storm-contrib project is a central repository for community contributions. However, many community members also choose to host Storm-related projects outside of storm-contrib. Everything in storm-contrib is licensed under the Eclipse Public License. storm-contrib contains everything from:
- Spouts: These spouts integrate with queueing systems such as JMS, Kafka, Redis pub/sub, and more.
- storm-state: storm-state makes it easy to manage large amounts of in-memory state in your computations in a reliable by using a distributed filesystem for persistence
- Database integrations: There are helper bolts for integrating with various databases, such as MongoDB, RDBMS's, Cassandra, and more.
- Other miscellaneous utilities
The Storm wiki has links to other notable Storm-related projects hosted outside of storm-contrib.