Realtor-owned multiple listing services are now required to be able to serve up listings data in a universally accessible format known as RETS, but MLSs are under no obligation to provide RETS feeds to their members.

Software developers and providers of services like IDX (Internet Data Exchange) listing sites have looked forward to implementation of the Real Estate Transaction Standard, or RETS, because it will in theory allow all computers that deal with real estate information to "speak" the same language.

Under a policy adopted two years ago, the National Association of Realtors mandated that all Realtor-owned MLSs be RETS compliant as of Dec. 31, 2009. And in most cases, MLSs are providing RETS-compliant data feeds to member brokers, say industry experts.

But as one Hawaii-based network of real estate brokers recently discovered, just because an MLS is RETS compliant doesn’t mean it has to provide access to RETS listings.

Hawaii Life Real Estate Services, which boasts of having grown from zero to 65 agents in 23 months, currently has access to RETS feeds from two of the three MLSs in the islands.

When it learned that the third MLS, Hawaii Information Service, had become RETS compliant, the company inquired about canceling its existing FTP and XML feeds from the MLS and replacing them with RETS.

RETS listings can be updated throughout the day, instead of once every 24 hours, and allow greater flexibility in developing applications for agents than FTP (file transfer protocol) and XML (extensible markup language) listings feeds, said Hawaii Life’s Justin Britt.

When Britt heard Hawaii Information Service had become RETS compliant, he said he expected he’d be able to get access to the MLS’s RETS server within a week.

Instead, he said he was told by a Hawaii Information Services sales representative that the MLS did not offer a RETS feed, and was under no obligation to do so.

When Britt checked with the Real Estate Standards Organization (RESO), the nonprofit that governs the development, maintenance and promotion of RETS, he was surprised to hear that this was true.

RETS feed not mandatory 

The RETS policy adopted by NAR in 2008 requires only that Realtor-owned MLSs demonstrate their compliance by using RESO’s online compliance checker, which verifies that they have a listings database up and running on a server that supports RETS.

But, Britt wondered in a recent Geek Estate blog post, if the goal of RETS is to create an industrywide standard for data exchange between MLS participants, why aren’t MLSs also required to provide a feed?

"My gut feeling is it was just an oversight," Britt said. If the matter is brought to the attention of NAR’s board of directors, Britt said he hopes NAR will require MLSs to provide access to RETS listings.

But Cliff Niersbach, NAR’s vice president of board policy and programs, said there’s been no request that the policy be changed.

Britt’s realization that MLSs are not required to provide RETS listings feeds soon became the topic of an online discussion among members of RESO’s board of directors.

"I can’t really argue with anything he states," said RESO board member David Harris, director of data management for "I know we have avoided the ‘NAR policy’ topic in the past, but it would be a huge win if we could work behind the scenes to understand the reluctance (if there is any) to the MLS in providing RETS."

Kristen Carr, a RESO board member since 2007, replied that there were "a ton of business reasons" why an MLS might not want to provide access to RETS listings, including staff skills and time, distrust of vendors, or a lack of appropriate agreements.

"I think it isn’t any of our business and we cannot tell an MLS how to conduct their business," said Carr, who was hired by RPR in February as vice president of industry relations.

Hawaii Information Service CEO Richard Eshleman told Inman News that the MLS does intend to make "a variety of RETS feeds available" in the second phase of its RETS compliance project.

"Our consultant is currently working on the documentation and updating the RETS metadata," Eshleman said in an e-mail. "He is on schedule to have the project completed by the end of June, and we expect to have RETS feeds available early in July."

RETS adoption

It’s a matter of debate how many other MLSs are RETS compliant but not providing RETS feeds.

Micheal Wurzer, president and CEO of flexmls developer FBS Data Systems, said he believes that Hawaii Information Service is "a very rare exception" and that the "overwhelming majority of MLSs provide RETS feeds."

All of the more than 100 MLSs that use flexmls provide RETS feeds, Wurzer said.

"Given the limited number of MLSs that do not provide RETS feeds, I don’t think this is a major problem," Wurzer added.

"That’s not to diminish the frustration those facing such a situation are experiencing, but it is the exception rather than the general state of affairs."

Wurzer agreed with Carr that "whether an MLS provides a RETS feed or not isn’t RESO’s business." He noted that all MLSs are required to provide IDX (Internet Data Exchange) and VOW (Virtual Office Website) feeds, and that the most common method of delivering those feeds is RETS.

Matt Cohen, chief technologist for Clareity Consulting, said "certainly the problem (of MLSs not providing RETS feeds) does exist," but it’s hard to say whether it’s a common one. Clareity Consulting provides information technology consulting to the real estate industry, and all of its MLS clients do provide RETS feeds, Cohen said.

Jim Harrison, president and CEO of MLSListings Inc. in California’s Sillicon Valley, said he "would expect it to be extremely uncommon" for MLSs to comply with NAR’s policy but not provide RETS feeds.

For one thing, MLSs (or their vendors) must have a RETS server up and running in order to verify RETS compliance, Harrison said. Then it’s a matter of enrolling bulk data customers, such as brokers or vendors, to enable them to pull data updates.

"RETS isn’t perfect, but it’s a fundamental service any broker and his vendors should expect from his MLS," Harrison said.

According to a 2004 NAR white paper, RETS was first conceived of in 1999, and most of the major MLS vendors had RETS solutions in place years ago, including FBS, Fidelity National Information Services, Interealty, MarketLinx, Offutt and Rapattoni.

Vendor perspective

Third-party developers that had incorporated RETS into their software by 2004 included eNeighborhoods, Homestore, McChristian, Showing Time, Supra, Tarasoft, Top Producer, WyldFyre and Zipforms.

Karen Kage, CEO of Michigan’s Realcomp II Ltd. MLS, said Realcomp currently provides a RETS feed for some vendors and brokers and is working toward moving all of its data feeds away from FTP and solely to RETS.

Kage said there are some concerns, including the fact that RETS access bypasses the "two factor" agent ID and password security authentication currently in use by the MLS, "which could result in a loss of control of the data and access to the data."

Kage said her information technology team has told her that there "can be a lot of support involved with RETS," as there are different versions of the standard. "This could be a barrier to MLSs offering this service if they do not have sufficient staff," she said.

The next version of RETS includes standard field names, "which should make this process much easier," Kage said.

Britt said he understands that "it’s not that (Hawaii Information Service) doesn’t want to have (a RETS feed), it’s that they have a custom-built MLS system and it (will) cost them money to implement."

He said that Hawaii Information Service initially didn’t seem to understand why Hawaii Life needed a RETS feed, or how the MLS’s members would benefit.

"The speed is the most important thing — having properties being updated several times a day is a huge advantage to our clientele," many of whom are assisting buyers and sellers of distressed properties that generate bidding wars as soon as they hit the market, Britt said.

From software developer Greg Robertson’s point of view, RETS represents a step in the right direction, but is still a far cry from true data standardization that would make it possible to write applications that work for users of many different MLSs.

RETS is a programming language that facilitates communications between an MLS server and brokerage computers, but it does not guarantee that the listings data from different MLSs will be fully compatible.

Robertson, co-founder of Cloud CMA developer W&R Studios, said the best hope on that front is that MLS vendors are currently developing their own APIs, or application programing interfaces, that would allow vendors to help themselves to listings data — with the authorization of MLSs.

"I think a lot of vendors would say, ‘Just let me grab the data myself,’ " Robertson said. "This could be the next big step, if you get three MLS providers to say, ‘Let’s make (APIs to the same data specifications)’ — maybe, finally, there will be some movement on standards."

If there was a common API for accessing listings of all MLSs using CoreLogic’s MarketLinx MLS application, for example, software developers could write code for that API rather than working with each MLS’s tech staff on compatibility issues, Robertson said. Developers would still have to get approvals from each MLS, but Robertson envisions MLS vendors playing a role in that process, too.

"It would be great if I could go to a MarketLinx, check what MLSs I want to work with my product, download the permission forms, send them in, get back terms, and in less than a month, maybe I’m working with 16 MLSs around the country," Robertson said. "That would be fantastic."


What’s your opinion? Leave your comments below or send a letter to the editor.

Show Comments Hide Comments


Sign up for Inman’s Morning Headlines
What you need to know to start your day with all the latest industry developments
By submitting your email address, you agree to receive marketing emails from Inman.
Thank you for subscribing to Morning Headlines.
Back to top
Only 3 days left to register for Inman Connect Las Vegas before prices go up! Don't miss the premier event for real estate pros.Register Now ×
Limited Time Offer: Get 1 year of Inman Select for $199SUBSCRIBE×
Log in
If you created your account with Google or Facebook
Don't have an account?
Forgot your password?
No Problem

Simply enter the email address you used to create your account and click "Reset Password". You will receive additional instructions via email.

Forgot your username? If so please contact customer support at (510) 658-9252

Password Reset Confirmation

Password Reset Instructions have been sent to

Subscribe to The Weekender
Get the week's leading headlines delivered straight to your inbox.
Top headlines from around the real estate industry. Breaking news as it happens.
15 stories covering tech, special reports, video and opinion.
Unique features from hacker profiles to portal watch and video interviews.
Unique features from hacker profiles to portal watch and video interviews.
It looks like you’re already a Select Member!
To subscribe to exclusive newsletters, visit your email preferences in the account settings.
Up-to-the-minute news and interviews in your inbox, ticket discounts for Inman events and more
1-Step CheckoutPay with a credit card
By continuing, you agree to Inman’s Terms of Use and Privacy Policy.

You will be charged . Your subscription will automatically renew for on . For more details on our payment terms and how to cancel, click here.

Interested in a group subscription?
Finish setting up your subscription