Is IDX Under Fire and Are VOWs Rising From the Ashes?

Jun 28, 2023 Michael Wurzer

The real estate socials have been buzzing the last week or so about Howard Hanna’s recent decision to opt-out of IDX and switch to only using VOW feeds to distribute their listings and power their web site Greg Robertson posted about it on Vendor Alley and then hosted a Twitter Spaces on the topic and Victor Lund published a post on the WAV Group blog as well.

My view is that, in the end, this likely is much ado about nothing, because sites will still be able to show the Howard Hannah listings via the VOW feed. Yes, VOWs require users to create an account and be logged in to see them, but sites like have proven long ago that there are effective ways to implement a combination of IDX and VOW experiences on a web site.

I think much of the uproar is that lots of sites rely on IDX only, including possibly some of the national portals, and so, for now, the listings are not showing at all on those sites. For example, at the time of me writing this post, 3301 E Derbyshire is an active listing on

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However, that same listing shows as “off market” on, indicating that has not yet implemented VOW feeds (you can see I’m logged in as “MW” below):

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And, which is a combo IDX/VOW site, shows the listing and indicates that users need to login to see it:

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One of the portal sites that has drawn the most attention in this case is Zillow, which also uses IDX (at least), but is still showing this listing even though HowardHannah is opted out of IDX:

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In announcing the switch to VOW, Howard Hannah specifically mentioned that they’d still be sending listings to Zillow, so some folks on Twitter have speculated that perhaps Zillow is still showing the listing because they have a direct feed from Howard Hannah whereas other sites do not. However, as you can see in the above image, Zillow is saying the listing is coming from the MLSNOW data feed, and so I’m guessing this is just a case where Zillow may not have implemented the IDX opt-out requirement properly or, if they’re using both IDX and VOW feeds from MLSNOW, they’re not following the VOW rules to require login for such listings as does. (Update: Folks on Twitter have reiterated that Zillow is getting a direct feed from Howard Hannah and is showing MLSNOW as the source, because MLSNOW is facilitating the direct feed. If that’s true, I’d recommend showing Howard Hannah as the source.)

In the end, though all of this certainly points out the complexity of IDX and VOW implementations, sites like show that a combo approach can be implemented well and I’m sure sites like Zillow and Homes will follow suit as will lots of IDX vendors providing sites to brokers and agents such that this debate about IDX and VOW will once again fade into the background.

A potentially related article was posted in Swanepoel’s Real Estate News site about eXp, indicating they’ve been in discussions with CoStar about a partnership with

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The article later refers to ” two or three other exclusive partnerships”, indicating that perhaps the discussions with were for an “exclusive” partnership as well. This might be a stretch, but, for an “exclusive” to be possible, wouldn’t eXp need to opt out of IDX to prevent those listings from showing on other IDX powered portals like Zillow? Of course, as discussed above, even opting out of IDX wouldn’t prevent sites from showing the listings using a VOW feed as Redfin does, so it seems unlikely the negotiations are for an “exclusive” deal unless eXp was intending to opt out of MLSs entirely, which really would be news.

Regarding the question above about whether MLS policy allows a broker Participant to opt out of IDX and send their listings to a designated portal, I chime in to the Twitter thread at one point to mention that the right for broker Participants to send their own listings wherever they want appears to be covered by the mandatory NAR policy Section 18 Right of Participant to MLS Data Feed of Listing Content (Policy Statement 8.3), which says:

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I also mention in the thread that FBS’s Spark Platform provides cost-free feeds to brokers of their own listings (though the MLS may still have a fee) and that includes contacts, saved searches, favorites, and other customer portal data in addition to listings. So, yes, brokers in MLSs using the Spark Platform certainly have the right and capability to send direct feeds of their own listings wherever they want. Is that better than IDX or VOW? I don’t think so but I think providing options to increase competition and experimentation on different models is important, and that’s what the Spark Platform has always been all about. Sites can implement direct feeds, IDX sites, VOW sites, and combination IDX/VOW sites using the Spark Platform, which makes it possible to automate compliance with opt-outs and disparate MLS IDX and VOW policies.

Let me close by referencing a Listing Bits podcast discussion I had a few weeks ago with Greg Robertson, Greg Fischer, and Andy Woolley from regarding’s switch from direct feeds to IDX. In that discussion, I recommended that MLSs create new licensing options for portals so they don’t feel forced to use IDX or even VOW feeds when those really aren’t a perfect fit to their use case. Even where companies like Zillow or CoStar become broker Participants and are entitled to IDX and VOW feeds, if the above discussion shows anything, it’s that complying with all these varied rules is a lot of work (hopefully lessened by the Spark Platform) and MLSs could create more consistency and options for both brokers and portals at the same time by rethinking the licensing of feeds to portals.

Along these lines, there’s been quite a bit of discussion and even draft proposals to combine IDX and VOW policies into one and perhaps such an effort could differentiate the case for how national high-traffic portals (even those provided by broker Participants) are licensed the MLS data. Until there’s a clear policy that differentiates these use cases, we’ll likely continue to see independent decisions by broker Participants to opt-out of IDX and thereby creating an inconsistent experience for consumers and broker Participants alike. This is as good a time as any to dig in and differentiate and simplify these different use cases to create a more certain listing distribution platform for everyone.