Real Estate Transaction Standards (RETS) Web API

What Is an API?

API, short for Application Program Interface, describes a data transfer method that eliminates the need to copy listings between servers. API technology creates efficiencies in the collection and use of MLS data by participants, vendors and MLSs.

Pursuant to the recommendations of the Multiple Listing Issues and Policies Committee, the NAR Board of Directors approved revisions to the National Association of REALTORS®’ Real Estate Transaction Standards (RETS) policy to require that MLSs implement the Web API standards described below. MLS organizations owned and operated by associations of REALTORS® are required to adopt and implement the Real Estate Standards Organization (RESO) Standards, including:

  • the RESO Data Dictionary by January 1, 2016;
  • the RESO Web API by June 30, 2016; and
  • will keep current by implementing new releases of RESO Standards within one (1) year from ratification.

Given the foregoing, the NAR MLS Policy Statement related to RETS was amended, as follows (underscoring indicates additions; strikeouts indicate deletions):

MLS Policy Statement 7.90, Real Estate Transaction Standards (“RETS”)

The integrity of data is a foundation to the orderly real estate market. The Real Estate Transaction Standards (RETS) provide a vendor neutral, secure approach to exchanging listing information between the broker and the MLS. In order to ensure that the goal of maintaining an orderly marketplace is maintained, and to further establish REALTOR® information as the trusted data source, MLS organizations owned and operated by associations of REALTORS® will comply with the RETS standards by December 31, 2009,and implement the RESO Standards including: the RESO Data Dictionary by January 1, 2016; the RESO Web API by June 30, 2016 and will keep current with the standard’s new versions by implementing new releases of RETS RESO Standards on at least one of the MLS’s servers within one (1) year from ratification. Compliance with this requirement can be demonstrated using the Real Estate Standards Organization (RESO) compliance checker Certification Process. (Amended 11/0914)

Benefits of API

Associations, MLSs and their members will benefit when implementing Web API. The benefits include:

  • Provides MLS participants/subscribers with improved MLS data access including faster updates/results, increased security, and ease of use in displaying property information.
  • The RESO Data Dictionary standardizes all available data fields for software programing and eliminates the need to “map” local MLS data. This will not preclude MLSs from using local terminology for naming data fields.
  • Standardized data fields enable vendors and programmers to develop tools, applications and other resources available from MLSs to MLS participants/subscribers without the challenges associated with locally implemented data definitions.
  • Less expensive for brokers and MLSs to reformat and use MLS data with a more mobile-centric focus.
  • Improved accuracy of MLS data with no degradation of information.
  • Gives MLSs, MLS participants/subscribers the same technology already being used by outside competitors, syndicators and aggregators.
  • “The next advancement in technology that REALTORS® deserve TODAY.”
  • “Plug and play for listing display.”

More information from RESO about Web API.

Additional Resources on RETS

NAR Topic: Real Estate Transaction Standards (RETS)
CRT White Paper: The RETS Web API and What It Means for Mobile and Real Estate