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RESO certifies systems that comply with real estate data standards. Certification ensures interoperability between technology systems that speak a common standards language.

The certification map shows MLS organizations that are Uncertified, Certified Legacy (on an older standard), Passed Current (technical testing is done) and Certified Current (the MLS has accepted the terms of certification). If your organization is ready to be tested for certification, have your technology vendor contact to get started.


RESO Map of Certified Organizations

RESO Certifies Data Dictionary on the Web API: MLSs Are Retiring RETS


The Certification Process

RESO’s certification process is now highly automated. It is primarily processed between RESO and the technical vendor.

  1. Compliance Testing: RESO uses access credentials supplied by the applicant’s technology vendor and verifies standards conformance for the system.
  2. Certification: Applicants whose systems pass testing are asked to confirm results, accept certification terms and are then granted certification from RESO.


Please have your technology provider contact RESO to initiate certification. They will complete technical testing with RESO staff, and we will notify your organization when your system is ready to certify.

In-Depth Certification Reports

Past RESO certifications were reported simply as pass or fail. Today, RESO Analytics publishes in-depth reports on the metadata, standard resources and fields, custom local fields, data availability, and server performance of certified systems.

MLS Certification Dashboard

You can view published reports from RESO certified organizations. Please join the RESO Transport Workgroup and Certification Subgroup sessions to learn more.

Certification Quick Facts

  • RESO is currently certifying on Web API Core 2.0.0 and Data Dictionary 1.7.
  • Certification on the most recent standard is classified as “Certified Current.”
  • MLSs systems that have completed technical testing but the MLS has not yet accepted the results are listed as “Passed Current.”
  • Certification on the previous most recent standard is classified as “Certified Legacy.”
  • Certification isn’t just for MLSs. Brokers and technology vendors with Web API servers are also certifying with RESO.

Certification by Organization Type