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WEB API Certification

RESO provides RESO Web API Certification for Multiple Listing Services, Association of Realtors, Technology Partners and Brokerages.  Any type of organization can apply for RESO Web API Certification.

Regarding fee schedules for Multiple Listing Services and Association of Realtors, the RESO Board of Directors has just approved that initial RESO Web API Certification for all RESO members who are current on their Data Dictionary Certification will be FREE. RESO will work directly with the MLS Technology Provider of the MLS/AOR that has their active Data Dictionary Certification to perform the RESO Web API Certification.  The MLS/AOR won’t need to apply directly for certification if they are a RESO member and actively data dictionary certified.  MLS/AOR organizations which do not qualify will need to apply for RESO Web API Certification directly and pay the associated fees.  For a detailed list of fees outside of the discount program, please review the RESO Certification Fee Schedule.   MLS/AOR organizations who choose to take advantage of the benefits of RESO certification must obtain direct certification, an MLS Technology Provider who acquires RESO Web API Certification does not extend certification coverage to the individual MLS.

The original Web API push was fostered by policy from National Association of REALTORS®. As an effort to drive opportunities for innovation and efficiencies in transmitting listing information, NAR requires that MLSs/AORs have the RESO Web API in place by June 30, 2016.  We know it’s possible for the majority of the MLS industry to meet the June 30th Web API deadline, as the process should be much faster and easier. Remember that you get more information about the RESO Web API and you can download the entire standards specification for free on our website here. And for specific questions about RESO Web API Certification, please visit the appropriate certification application page or just send an email to

For Multiple Listing Services and/or Association of Realtors, please visit Certification for MLSs to review the steps for certification and apply for RESO Data Dictionary, RESO Web API and/or RESO RETS Certification.  For Technology Partners and Brokerages, please visit Certification for Technology Partners to to review the steps for certification and apply for RESO Web API and/or RESO RETS Certification.

Official Messaging from the National Association of Realtors regarding the June 30, 2016 standards adoption policy deadline for the RESO Web API

  • There will be a 45 days non-formalized grace period to handle scheduling and timing issues related to conformance.
  • Our focus is not on consequences but on supporting implementation and working directly with MLSs to address obstacles.
  • Only those REALTOR® associations and REALTOR® association-owned MLSs that are in compliance with mandatory NAR policies are eligible to receive coverage from the NAR-provided insurance policy.
  • In addition, association charter revocation is always a potential consequence of failure to comply with any mandatory NAR policy.

It’s important to keep in mind that trust – at all levels of the REALTOR® organization – is essential to the successful delivery of services to our members. The real estate profession itself exists on trust. Clients and customers trust the REALTORS® they work with. REALTORS® need to – and do – trust each other. Associations and MLSs rely on the word of their members. And, members need to be able to rely on their REALTOR® associations and MLSs to comply with the policies adopted by the NAR board of directors which consists of more than 800 of their fellow REALTORS®. When NAR receives any complaint from a REALTOR® or a member board regarding an MLS’s failure to implement a mandatory policy, NAR staff follows up with that MLS directly. We know that most MLSs have worked hard these past couple years to improve their systems to comply with RESO standards for the benefit of their membership and NAR greatly appreciates that effort.

RESO Web API Technical Information

RESO Web API Certification Testing Rules

The RESO Web API Server Testing Rules document describes the tests that will be performed during the certification process. The documentation also includes information on what of the OpenID and OData standards are tested during RESO Certification Testing.
The RESO Web API Client Testing Rules will be made available once approved by the appropriate RESO Work Groups and Committees.

OpenID Certification Testing

Certification applicants may be able to test their own server’s security at RESO Staff will confirm the findings during the certification testing process. Discovering issues through this testing process before applying for certification could reduce the time required to return certification results.

OpenID Connect Redirect URI

The RESO Web API uses OpenID ( for server access security. Applicants setting up their OpenID system should use “” as the redirect_uri.

DLU October 13th, 2016