Certification for MLSs


The RESO Certification process allows your MLS to test programs and platforms for conformance to RESO Standards. MLSs and other organizations that distribute real estate data are eligible for obtaining certification on the RESO Data Dictionary. Understanding the Certification process will help you better navigate being Data Dictionary Certified.  MLSs, Technology Companies and Brokerages can also obtain official RESO Web API Certification.

Data Dictionary Certification

The Data Dictionary serves as the real estate industry’s “Rosetta Stone” for data fields. An estimated 750+ MLS organizations and hundreds of other technology firms gather real estate data. But what good is it if the data cannot be shared or understood? The Data Dictionary ensures that each system “speaks” the same language. This new common standard defines real estate data fields – fields that contain the most important property listing information – and that data is presented using consistent terms and data structures. The RESO Data Dictionary creates a common language so the real estate information can be more easily shared and understood.

A spreadsheet (Excel file .xslx format) that lists the Data Dictionary core fields – those that must be compliant to receive RESO Certification – are located here.

RESO Web API Certification

The RESO Web API is a next generation real estate data transport using the latest industry standards. The RESO Web API is build upon the open-sourced technologies of OData, OpenID Connect, and JSON. New Web API servers and applications can be created more quickly using these commonly used technologies.  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 will not need to apply directly for certification if they are a RESO member and actively data dictionary certified.  RESO does request those MLSs still contact their MLS Technology Partners to ensure readiness and keep in touch with RESO on certification status.  MLS/AOR organizations who do not qualify for FREE certification 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.   Each individual MLS must obtain direct certification, an MLS Technology Provider who acquires RESO Web API Certification for a product offering does not extend certification coverage to the individual MLS.

Benefits of Certification

Compliance with the NAR mandate is an obvious and immediate benefit, but the business justifications make this truly a “no brainer,” including:

  • Fewer errors: The Data Dictionary provides simplified data integration. This means data can move between systems without losing information, resulting in fewer errors.
  • Lower maintenance costs: Data translation costs are reduced because data loss is lowered with consistent data definition. You’ll be spending less time calling your IT department or MLS technology provider to fix the problems that occur with data loss.
  • Faster innovation, quicker iteration: MLSs, brokerages and technology partners all deal daily with data feeds and the challenges that not having standards bring. By creating common standards, the need for your customers – brokerages – to create complex workarounds to “solve” for the differences in core data fields that are defined differently by MLSs is eliminated. This will foster faster innovation and the ability to change and improve new technology that will serve MLSs, brokerages and agents, and in the end, benefit home buyers and sellers.
  • Staying current, relevant: Lessons from other industries have shown that if an industry lags in creating standards, someone else from outside the industry will. RESO mission is to help organizations streamline the real estate industry through the adoption of standards to drive efficiency throughout the real estate industry. Getting certified keeps your MLS current, relevant and at the forefront of change.

MLS Certification: The 5-Step Process

Step 1 – Contact your MLS Technology Partner

Before you apply for Certification, you need to have implemented the required Data Dictionary specifications or RESO Web API specifications before testing of your system. Your first step must be to immediately contact your MLS technology provider (or your internal IT department if you provide your own technology) and ask them what their plan is to help you become Data Dictionary and/or RESO Web API Complaint per the NAR mandate. Work with your technology partner or internal IT department to ensure the Data Dictionary and the RESO Web API is implemented within your multiple listing service system.

Data Dictionary implementations may be tested prior to completing the certification application. The Data Dictionary Testing Tool is publicly available for any organization to check their compliance level prior to official certification testing.  RESO released a publicly available RESO Web API Testing tool in the summer of 2016.

Some MLS Technology Partners have provided RESO specific messaging and instructions regarding certification for their respective customers and that information can be located here.

Step 2 – Complete the Application

When you are ready to have your system tested for Certification you will submit an Application for Certification to RESO. RESO recommends not applying until no more than a few of weeks before you are ready for final certification testing.

Next, RESO reviews the application and verifies the information you provided and our Certification team will contact you to clarify any information if necessary. Start the Certification Application

Step 3a – Data Dictionary Compliance Testing

During this phase, RESO runs the appropriate tests for your system comparing the local MLS data dictionary implementation against the RESO testing rules.
In some special instances, not all information required to evaluate a Data Dictionary Certification application can be submitted through the online certification application form. The Data Dictionary Supplemental Application Information (SAI) can provide RESO Certification staff additional information to help with the Certification Testing. Once RESO Certification staff starts testing, they will alert you if there are issues which will might require filling out the Data Dictionary Supplemental Application Information spreadsheet in order to provide the RESO Compliance Department with specific information to help complete the certification process successfully. Please refer to the “Instructions” on the first tab of the linked spreadsheet for more information if you are requested to do so by RESO Staff.

Step 3b – RESO Web API Certification

During this phase, RESO runs the appropriate tests for your system comparing the local API Implementation against the RESO testing rules for the RESO Web API v1.0.2.

Once RESO Certification staff starts testing, they will alert you if there are issues which will might require working with you directly or with your affiliated MLS Technology Provider in order to provide the RESO Compliance Department with specific information to help complete the certification process successfully.

Step 4 – Certification or Troubleshooting

You will be RESO Certified if your programs and system meet the required RESO standards, and a Certificate will be provided to you. RESO will troubleshoot issues and work with you if you do not meet the standards.

Step 5 – Electronically Sign the Certification Trademark Agreements

In order to use the approved RESO Certification Logos, you must electronically sign the “Trademark Agreement document.” The RESO Trademark Agreement is emailed to you after your application is approved. The Trademark Agreement allows applicants that have earned Certification use the official RESO Certification logos and badges to market and promote their Certified status. It also allows RESO members to display RESO member logos.

More About Data Dictionary Certification

The Data Dictionary is independent of any data transport system. Because of this, Data Dictionary Certification is only concerned with a system’s data structure. It does not matter what technology is used to transport the data, only that the data is structured correctly. Each data transport method (RESO Web API, RETS 1.x, etc.) will have its own set of implementation rules that must be followed.

More information about the Data Dictionary is available at https://www.reso.org/data-dictionary/. Additional questions on how to use tool or any information found within the tool may be sent to certification@reso.org.

List of Data Dictionary Certified MLSs

A list of MLSs that have been RESO Data Dictionary Certified may be viewed at https://www.reso.org/certificates.

Separate MLS/AOR Organizations who Share a Core MLS System

For Multiple Listing Services and Association of Realtors that are separate corporate organizations and share a core MLS system (not a data share but share add/edit and common listing distribution), there is a special RESO Certification Program with discounts available based upon the specific situation. Please contact info@reso.org for more details.

Important Data Dictionary Information

Standard Component Instructions Rules
Data Dictionary 1.6 RESO Data Dictionary Certification Overview v1.6.0 RESO Data Dictionary Certification Testing Rules v1.6.1
Data Dictionary 1.7 RESO Data Dictionary Certification Overview v1.7 RESO Data Dictionary Certification Testing Rules v1.7

Important Web API Information

Standard Component Specification Rules
WEB API 1.0.2 RESO Web API Version 1.0.2 RESO Web API Server Testing Rules v1.0.2.1
WEB API 1.0.3 RESO Web API v1.0.3 RESO Web API Server Certification Testing Rules v1.0.3

Important Links

  • Awarded Certificates: A list of those certificates currently awarded by RESO.
  • RESO Certification Fee Schedule. The fees for RESO Standards Certification vary based on membership type and organization size. This document describes the current costs.
  • Data Dictionary Supplemental Application Information (XSLX):The Supplemental Application Information (SAI) will assist the RESO Compliance Department with the Data Dictionary evaluations. It provides information required by the RESO Compliance department to perform the evaluation tests and ensure compliance.
DLU December 23rd, 2019