| Feature | IDX | VOW |
|---|---|---|
| Registration | Usually not required | Required, with broker relationship |
| Data shown | Public listing fields | Can include expanded data, subject to rules |
| Typical use | Public search on agent sites | Client accounts and deeper detail |
| Rules | Vary by MLS | Vary by MLS |
Glossary · Listings & the MLS
Internet Data Exchange (IDX)
Internet Data Exchange (IDX) is the set of rules and technology that lets real estate brokers display each other's MLS listings on their own websites. Participating brokers consent to have their listings shown by other members, subject to attribution and display standards. IDX generally shows publicly available data without requiring visitors to register, which is why an agent's site can display a broad range of homes.
Also known as: IDX
How does IDX work?
A broker who joins the MLS opts into IDX, agreeing to share listings and to display others' listings under set standards. An automated feed or plugin pulls listing data into the broker's website, refreshing regularly. Display rules cover attribution, required fields, and update frequency, and they vary by MLS.
Technically, IDX works through a data feed, often called RETS or the newer Web API, that syncs MLS listings to a broker's site. Many agents use a third-party IDX vendor that formats the feed into searchable results.
Because participation is reciprocal, a broker must share their own listings to display others'. MLS rules dictate what must appear, such as the listing broker's name, and how often the data must update, commonly every day or more often.
Why does IDX matter?
IDX lets an individual agent's website show most homes on the market, not just their own listings. That keeps buyers browsing on the agent's site rather than leaving for a national portal, helping the agent capture leads while giving consumers convenient access to inventory.
For consumers, IDX means a small brokerage site can feel as comprehensive as a big portal. For agents, it turns a website into a lead source, since visitors can search, save homes, and request showings directly.
How is IDX different from a VOW?
IDX generally displays public listing data without requiring visitors to register or log in. A Virtual Office Website (VOW) requires registration and a broker-consumer relationship, which lets it show expanded data. The registration requirement and the resulting depth of data are the core differences.
Think of IDX as the open storefront and a VOW as the members area. IDX shows what is broadly public, while a VOW can reveal more once a consumer creates an account and agrees to terms, subject to MLS rules.
Worked example. For example, a solo agent adds an IDX search tool to her website. A buyer visits, searches homes under 600,000 dollars, and browses hundreds of active listings from many brokerages, each showing the listing broker's name. The buyer saves three homes and requests a showing, all without leaving the agent's site.
Common mistakes with Internet Data Exchange
- Do not assume IDX shows every field an agent sees inside the MLS, since public display rules often restrict certain data.
- Avoid treating IDX data as instant, because feeds refresh on a schedule and a status can lag behind the MLS.
- Do not remove required attribution like the listing broker's name, as that violates IDX display rules and can risk MLS penalties.
- Sellers should not assume opting out of IDX helps them; limiting exposure usually reduces buyer reach.
- Do not confuse IDX with a VOW, because IDX generally needs no registration while a VOW does and can show more data.
Related terms
Term
Multiple Listing Service (MLS)
A private database where brokers share property listings and offers of cooperation and com
Define TermVirtual Office Website (VOW)
A brokerage website that shows expanded MLS data to registered consumers under a broker re
Define TermPocket Listing
A property marketed privately by an agent without being entered into the MLS.
Define TermActive, Pending, and Sold Status
The core MLS statuses that describe where a listing stands in the sales process.
DefineInternet Data Exchange FAQ
Do I have to register to search IDX listings?
Generally no. IDX sites usually let you search public listing data without creating an account. Registration is a feature of a Virtual Office Website, or VOW, which requires a broker-consumer relationship to show expanded data. Some IDX sites still ask you to register to save searches.
Why do IDX listings show another broker's name?
IDX display rules require attribution to the listing broker, so listings shown on one agent's site credit the brokerage that actually holds the listing. This keeps the source clear and complies with MLS policy. Removing or hiding that attribution can violate the rules and risk penalties.
How often does IDX data update?
Update frequency is set by each MLS, but many require refreshes at least daily, and modern feeds often sync more frequently. Because updates run on a schedule, a listing status shown on an IDX site may briefly lag the live MLS. Confirm current status with an agent.
Can any website display IDX listings?
No. Only brokers and agents who are MLS members and opt into IDX may display the feed, and they must follow the display rules. Third-party vendors can build the site, but the participation and data rights run through a licensed MLS member. Rules vary by MLS.
Is IDX free for agents?
Not entirely. Agents typically pay MLS dues plus a fee to an IDX vendor or platform that formats and hosts the feed. Costs vary by MLS and vendor. Participation is also reciprocal, meaning an agent must share their own listings to display others' through IDX.
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