What is IDX? A plain-English guide for real estate websites

IDX in plain English

IDX stands for Internet Data Exchange. It is the MLS policy that lets real estate brokers show each other’s listings on their own websites. The National Association of REALTORS (NAR) describes it as giving MLS participants the ability to authorize “limited electronic display” of their listings by other participants.

In practice, IDX is the reason a two-person brokerage can offer a full search of every active home in its market, not only its own inventory. Each participating broker agrees to let others display its listings and, in return, gets to display theirs.

IDX is a policy and a license, not a piece of software. The software comes from an IDX provider, which takes the MLS data and turns it into search forms, map results, listing detail pages and lead capture on your site.

Who can use IDX

IDX rights belong to the MLS participant, which in most MLSs is the principal broker of a firm. NAR’s Handbook on Multiple Listing Policy says IDX display covers websites, mobile apps and audio devices under the participant’s control.

Agents are the most common question. Under NAR’s model policy, an MLS may, as a local option, let non-principal brokers and sales agents run IDX displays with their participant’s consent. The broker stays accountable either way. MIBOR’s data licensing page, for example, says any IDX display by a broker’s licensee is subject to that broker’s oversight and must include the firm’s name or logo.

A few other points about participation:

• It is reciprocal. Doorify MLS explains that a participant who opts into IDX lets other participants display its listings and gains the right to display theirs.
• Brokers can stay out. Canopy MLS notes that if a participant chooses not to take part, that firm’s listings cannot appear on other members’ websites.
• Sellers can opt out. NAR policy lets a seller direct that the listing, or just the property address, be kept off the internet.

If you are an agent, start the conversation with your broker. Our IDX websites for agents page covers what that looks like, and brokers can see how we handle brokerage sites.

How listings get from the MLS to your website

There are four links in the chain.

1. The listing goes into the MLS

A listing agent enters the property into the MLS. The record holds public fields such as price, photos and remarks, plus confidential fields meant only for other agents, such as showing instructions and security details.

2. The MLS licenses a data feed

The MLS makes IDX data available under a written agreement. CVR MLS, for example, requires a license agreement among the MLS, the participant and the data vendor, and it requires participants to tell the MLS before they start displaying IDX. Many MLSs now run these licenses through MLS Grid; Canopy MLS and MIBOR both route data requests that way. For MLSs owned by REALTOR associations, NAR policy requires that data to be available over the RESO Web API, which we explain in IDX vs VOW vs RESO Web API.

3. The IDX provider processes the data

The provider pulls the feed, keeps it current, drops fields that cannot be shown to the public and applies the display requirements. A good provider builds attribution and disclaimers into its templates so every listing page carries them automatically.

4. Your site shows search and listing pages

Visitors see search forms, map results and listing detail pages, usually with options to save a search, get alerts or request a showing.

Common IDX display rules

NAR publishes model IDX rules, but each MLS adopts and enforces its own version. The table shows requirements that appear in NAR’s handbook and in individual MLS rules. Always check the current rules for every MLS you display.

Other points worth knowing:

• Statuses vary. NAR policy requires MLSs to provide publicly accessible sold information for IDX displays, while MLSs may bar expired and withdrawn listings. CVR MLS lists both as restricted.
• Multiple MLSs. NAR’s handbook allows you to combine listings from several MLS IDX feeds if you hold participatory rights in each one and every display follows the IDX rules.
• Co-branding. MLSs that allow advertising on IDX pages may ban deceptive co-branding. NAR’s handbook presumes co-branding is fine when the participant’s logo and contact information are larger than any third party’s.

Because these details change from market to market, our MLS directory collects notes on individual MLSs.

Framed vs. on-domain and subdomain IDX pages

How IDX pages are delivered affects whether your domain gets credit for them. There are four common setups.

Framing is the fastest option. NAR’s handbook recognizes framing of an association, MLS or other public site, with that site’s permission, as an alternative way to display listings. Canopy MLS even offers an IDX search tool in its Matrix system that brokerage and agent sites can frame. The trade-off is that the listing pages are not yours.

Subdomains are the middle path most IDX Broker sites use. By default, IDX Broker serves pages from a subdomain of idxbroker.com, and its getting-started guide suggests switching to a subdomain of your own domain instead. Its documentation states that a custom subdomain lets search engines credit your domain as the content author for your IDX pages. A “wrapper” then makes those pages match the rest of your site, and IDX Broker’s WordPress plugin, IMPress, can create a dynamic wrapper for you. IDX Broker can also generate an XML sitemap to submit to Google.

No setup guarantees rankings. Many sites in your market show the same MLS listings, so original local content, such as neighborhood pages and market reports, is what sets your site apart.

IDX vs. syndication portals

People often confuse IDX with syndication, but they work differently. Doorify MLS’s comparison sums it up:

At Doorify, “Coming Soon” listings appear in IDX but are not sent to syndication channels. Other MLSs may handle that status differently.

The practical difference: syndication puts your listings on portals, while IDX puts the whole market on your website, where the leads come to you.

What an IDX provider like IDX Broker does

An IDX provider sits between the MLS and your website. Based on IDX Broker’s own materials, that includes:

• MLS data access. IDX Broker says it covers hundreds of MLS data providers in the United States, Canada and internationally.
• Search and listing pages. Map search, results pages, listing detail pages and saved links for specific areas.
• Lead capture. Registration prompts with adjustable settings and alerts when a new lead signs up.
• WordPress integration. The IMPress plugin adds search widgets, listing showcases and wrapper setup.
• Developer access. An API and developer partner program for custom IDX-powered sites.
• Approval workflow. Your account can be active while MLS approval is still in progress, with an access code so work on the site can continue.

Sleek Web Designs is an IDX Broker developer, so our job is the layer on top: WordPress design, wrapper and subdomain setup, compliance checks and content. Agencies that build sites for agents can partner with us.

How to get started

1. Confirm eligibility. Brokers check their MLS participation; agents get their broker’s written consent and confirm the MLS allows agent IDX displays.
2. Choose an IDX provider your MLS accepts. Ask whether the provider already works with your MLS.
3. Sign the MLS paperwork. This is usually an IDX or data license agreement, sometimes signed through MLS Grid.
4. Plan your domain setup. Decide between a custom subdomain and an on-domain integration before launch.
5. Check compliance. Confirm attribution, disclaimers, restricted fields and refresh timing against your MLS rules.
6. Add local content. Build community pages and saved searches that give visitors a reason to stay.

Want to see how this looks in practice? Browse our live IDX demos to try map search, listing pages and lead capture on a working WordPress site, then visit Get Started to see how sign-up and MLS approval work.

Frequently asked questions