Sleep occupies a third of our lives and helps to relieve the physical and mental fatigue of daily life and lead a smooth daily life. Therefore, it is possible to obtain an improvement effect that can enhance the quality of life based on the understanding of sleep time and quality through sleep monitoring. With the growth of the sleep market, various sleep monitoring products combined with ICT technology are being launched, and these products are mainly composed of dedicated apps and sensors. The use of products composed of such dedicated software for each sensor is a major limitation in service operation because it is difficult to integrate with existing service data and difficult to share data with other services when changing the product or using it with other services. This Recommendation introduces a way to provide an open, interoperable API for smart sleep management devices and sleep services. In order to provide an individual with optimal sleep, data collection, analysis, and customized services on individual sleep are required. For this, interoperability between IoT-based sleep management devices and services must be secured. Interoperability of services covered by this Recommendation includes interoperability of data and interoperability at the API level.