Abstract: Systems and Methods disclosed herein relate to providing a message to an application programming interface (API). The message includes a request for data from a data model, a submission of data to the data model, or both; and a host selection between: a representational state transfer (REST) host and a subscription-based application programming interface (API) host, wherein the REST host receives REST-based messages and the subscription-based API host receives messages in accordance with a standard of the subscription-based API host; wherein the request for data, the submission of data, or both are configured to create, delete, modify, or any combination thereof data related to a smart-device environment structure, a thermostat, a hazard detector, or any combination thereof stored in a data model accessible by the API.