Zetta is an open-source platform built on Node.js for creating Internet of Things (IoT) servers that run across geo-distributed computers and the cloud. Zetta uses REST APIs, WebSockets and reactive programming, making it ideal for assembling many devices and orchestrating interactions among them. Its architecture aims to facilitate the creation of scalable and interactive IoT applications that can easily integrate with web technologies.Zetta\'s design is modular, which allows developers to create reusable components known as "apps," that model specific device behaviors and interactions. This provides a powerful way of defining device interactions at a high level and linking devices together to form complex IoT solutions.