The RESO Web API specification provides an open standard for web-based API (Application Programming Interface) access to real estate data using the common REpresentational State Transfer (RESTful) approach. RESO’s move toward a RESTful standard is meant to facilitate and encourage access to real estate information directly from web, mobile, social and other web-based applications.
OData (Open Data Protocol) is essentially a system of rules for interacting with data via RESTful web services. It supports the description of data models and the editing and querying of data according to those models. The RESO Web API uses OData as its underlying protocol which serves as a set of fundamental building blocks.
RETS is an older standard that is proprietary to the real estate industry. It has been deprecated (no longer supported) because the industry is moving to a more well-known technology standard. RETS created great value for 20 years, and it is still in use, but the conversion to Web API is underway.
RESO does not provide MLS real estate data. RESO creates the standard for the data, and other organizations build technology based upon it. Brokers and technology companies should go directly to MLSs to request data via the Web API. MLSs owned and operated by REALTOR® associations are required by the National Association of REALTORS® to have production-level access available to their data via Web API.