The JellyFish Lighting API is a system in which JSON requests and responses can be sent and received over a Local Area Network via web sockets to manipulate the performance of the JellyFish Lighting system. This includes commands regarding patterns, running patterns, minor adjustments to patterns, powering on and off the system, and more.
The JellyFish Lighting system and its robust API allows great functionality and customization when used properly. The documentation in the link will provide you with a good baseline knowledge of how the system works, how to configure requests, and how to effectively interact with the system. The accompanying API Explorer application can be a great resource to help you see how requests should be structured, as well as the workflow of such requests. In addition to the provided resources, using a web socket tester can be very helpful.