Development This developer section is for anyone wanting to either write code which directly accesses the OpenNMS Horizon API, or to contribute directly to the project. It assumes some familiarity with concepts for deploying and running OpenNMS components described in the Deployment and Operations sections of this manual. This section covers the following topics: How to build Horizon from source Enhance Minion running in Karaf OSGi container Enhance the Topology visualization Create GraphML custom network topologies Enable CORS support Develop against REST APIs Write and publish documentation Integration in environments using AMQP Working with OSGi in OpenNMS Secure Credentials Vault Build from source