Essential technology for Internet of Things (IoT) devices includes connectivity protocols and sensor technology. Connectivity protocols like MQTT and HTTP enable devices to communicate and share data over networks. Sensors collect real-time data from the environment, allowing devices to respond intelligently. IoT architecture also requires cloud computing for data storage and processing, and analytics for interpreting collected information. Together, these elements facilitate the seamless operation and management of IoT ecosystems, enhancing smart home applications, industrial automation, and more.