What Is IDX in Real Estate?
IDX lets eligible real estate professionals display certain MLS listings on a public website. Learn how it works, who can use it, and what to check before choosing a product.
IDX stands for Internet Data Exchange. It lets eligible agents and brokerages show permitted MLS listings on a public website or app. The broker and local MLS determine who can use it and what can appear.
Consumers usually experience IDX as the property search on an agent or brokerage website. They can browse available homes and, depending on the product and local rules, save searches, register, or contact the real estate business. IDX is not the MLS itself. The current NAR IDX policy defines the national baseline, while each local MLS controls important details. When procurement is the next decision, use the IDX website shortlist and pre-purchase test to verify the exact local configuration.
How IDX gets listings onto a website
The website is the last part of a chain. Separating the steps makes vendor language much easier to evaluate.
- A brokerage participates in a local MLS.
The participant is usually the principal broker or firm. Affiliated agents and staff generally work under that participant's responsibility.
- The MLS authorizes a public IDX use.
Local rules determine who may operate the display, which listings and fields may appear, and what attribution or other display requirements apply.
- The eligible listing data is made available.
The MLS or its technology provider supplies the approved data to the participant, vendor, or development team.
- A product turns the data into a public experience.
The chosen product and its implementation determine the property search, page design, URL behavior, lead forms, hosting setup, performance, and connections with the rest of the website.
A vendor is common, but it is not part of the definition of IDX. A participant can also commission an approved custom implementation. In either case, data permission and website quality are separate questions. A brokerage with an existing IDX website can use the IDX SEO service to improve the site's pages, controls, listing lifecycle, and measurement.
What is an IDX feed?
“IDX feed” is useful shorthand for the licensed listing data made available for an IDX display. It is not the name of one universal delivery method.
- IDX feed
- The authorized listing data used for a public IDX display.
- IDX integration
- The technical connection and website experience built around that data.
- IDX website
- A real estate website that includes an authorized IDX property search or listing display.
- IDX vendor
- A company that turns authorized data into a search product, website feature, or broader real estate platform.
Some systems use the RESO Web API to exchange real estate data. RESO standardizes how systems communicate. Data rights come from the MLS, while technical credentials may be issued by the MLS or its software provider.
Read IDX versus MLS for the full relationship, including VOWs and syndication.
Who can use IDX?
IDX rights generally begin with the brokerage or firm that participates in the local MLS. An affiliated agent may be allowed to operate a website under the participant's control, but that arrangement varies. The NAR participant definition places that role with the principal broker or firm. An agent should confirm the arrangement with the broker and local MLS before buying a website or signing a vendor contract.
Coverage varies too. Seller choices, local status rules, property classes, data-sharing agreements, and display restrictions can all change what appears. Office-exclusive or delayed-marketing listings may be inside the professional MLS workflow without being available through public IDX. The current multiple listing options policy is one reason that “all listings” should be verified rather than assumed.
What IDX is useful for
IDX can give visitors a convenient way to explore available properties without leaving the agent or brokerage website. A well-chosen product can support browsing, saved searches, registrations, listing inquiries, and follow-up inside the business's wider customer journey.
IDX is a property-search feature, not a complete marketing strategy or a guarantee of traffic, leads, rankings, or user experience. Its cost and technical complexity are justified only by a clear role in the customer journey.
Before buying, use the IDX website shortlist and pre-purchase test.