Nowadays, the connected devices and services need differentiate tailored connectivity to satisfy diverse requirements. To simply provision of a large number of connected devices in a time-efficient way, Ericsson provides a SaaS solution Ericsson Device Connection Platform (DCP). Hence, a notification service is required to achieve real-time interaction, and a subscribe-notify web-services API is required to define the selected notification service based on DCP. However, it is difficult to choose a notification system due to lacking systematic approaches. In the view, I present six comparison points to compare current push notification products. My aim is to propose proposals to design a subscribe-notify web-services API. In an effort to further understand how push notification mechanisms work, I (1) explain Event Notification Service (ENS) technologies; (2) recommend to use the publish/subscribe (pub/sub) paradigm to define the API for DCP; (3) compare current push notification products by using six comparison points as the systematic approach. Six comparison points are basic information, functionalities, licenses with usage fees covering usage limits, security, supporting details and supported platforms/OS in terms of performance. In the case, Pushwoosh and AeroGear UnifiedPush Server provide appropriate notification systems to satisfy diversified demands for different scale enterprises
