What Is IDX (Internet Data Exchange) – The Complete Guide

Displaying property listings online is crucial in real estate today, and IDX (Internet Data Exchange) is extremely valuable in making this happen. A study by the National Association of Realtors (NAR) found that the internet is crucial for homebuyers of all ages, with 97% using it to find homes.

Realtors and brokers rely on the Multiple Listing Service (MLS) for sharing property info, and IDX helps integrate MLS listings into your website.

Are you curious about how IDX improves your website with MLS listings? Here’s what you need to know.

What is IDX?

IDX, created by the National Association of REALTORS®, is a policy under which brokers exchange permission to share and show each other’s listings online. It’s also called Broker Reciprocity, showing how brokers work together. 

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Even though IDX is a policy, it’s often used to discuss the list of properties from an MLS System. It also refers to the rules about how the property information is shown, which can differ for each MLS® System.

The History of IDX

Now that you know what IDX is, you need to know that before it’s appearance, only Realtors with access to the MLS could provide property information to consumers. This situation made the search process slow and inefficient. 

With the growth of the internet, IDX was created to enable direct access to property listings, empowering consumers to search independently.

In the early 2000s, NAR formed a work group to improve real estate applications on the internet for better client service while preventing misuse. 

As a result, the policy allowing MLS participants to display others’ listings on their websites was refined and revised several times, with the most recent changes on January 1, 2021. 

How Does IDX Work with MLS?

IDX, or Internet Data Exchange, facilitates the sharing of MLS listings among real estate professionals. The IDX protocol relies on agents agreeing to share listing information, overseen by MLS boards as the system’s gatekeepers. 

When a real estate agent adds a property to the MLS, it becomes available through a data feed for other MLS agents to use on their websites.

Initially, each MLS board had its own data feed, but they are now consolidating to create larger feeds, combining all area listings without merging the associations.

How IDX works – Illustration

Most MLS boards have adopted the IDX system, making buying and selling property easier for consumers.

Integrating an IDX/Data feed into your realtor website is essential nowadays. The chosen option should ensure automatic listing updates and provide various ways to showcase your listings and others.

To fully utilize the potential of IDX for your real estate business, explore how MLSImport can assist in creating a robust real estate website.

Which are the terms commonly used in relation to IDX?

IDX agreement / IDX Real Estate License

An IDX (Internet Data Exchange) agreement is a contractual agreement between a real estate agent or broker and a Multiple Listing Service (MLS) outlining the terms and conditions for the agent or broker to display MLS listing data on their website. 

This agreement typically specifies the rules and guidelines for how the agent can use the IDX data, including displaying property listings and using MLS information for marketing purposes.

The IDX agreement often includes provisions related to data usage, data sharing, property display rules, and compliance with MLS regulations. 

It also outlines the responsibilities of the agent or broker in maintaining the accuracy and integrity of the MLS data displayed on their website. 

Additionally, the agreement may cover aspects such as the duration of the contract, any fees associated with IDX usage, and the obligations of the agent or broker to adhere to specific IDX policies set by the MLS.

IDX compliance standards

IDX compliance standards are regulations real estate agents, and brokers must follow when showing MLS data on their websites. 

🔏 Privacy Policy
Websites using IDX must have privacy policies in place, particularly regarding the handling of consumer information gathered through the website.

These rules guarantee that the data is used correctly and meets industry and legal standards. They cover data accuracy, usage, property display, and consumer privacy protection. 

Adhering to these standards maintains data integrity, builds client trust, and promotes ethical practices in the real estate industry.

IDX feed / IDX data feed

An IDX feed, or IDX data feed, is a stream of real estate listing data from an MLS given to agents for their websites.

It allows agents to display current property listings in a standardized format. Using an IDX feed ensures website information stays updated and matches the MLS database, giving visitors accurate property details.

IDX information

IDX information includes real estate listings from an MLS, provided to agents for display on their websites. 

It contains property details like prices, descriptions, and images, helping agents offer comprehensive and current listings to their website visitors and making property searches easier for potential buyers.

IDX listings

IDX listings are properties from real estate agents or brokers displayed on their websites using the Internet Data Exchange (IDX) system. These listings are part of the agreement and data feed provided by IDX.

They come from a Multiple Listing Service (MLS) and provide detailed information like pricing, property descriptions, and images to help potential buyers search for their new home. 

These listings enable agents to offer a comprehensive view of available properties, making it easier for buyers to find and explore potential homes.

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IDX website

An IDX website is a real estate agent or broker’s site that uses IDX technology to show property listings from an MLS. 

It helps agents offer visitors an up-to-date view of available properties on their site. 

These sites often have advanced search options, making it more straightforward for users to find properties based on location, price, and features. 

They aim to enhance the user experience and help potential buyers find properties that suit their needs.

IDX technology

IDX technology allows agents to display MLS property listings on their websites, making it convenient for potential buyers to explore available properties without leaving the agent’s site. 

This integration enhances agents’ online presence and streamlines the property search process for their website visitors.

IDX plugin

IDX Plugin is a software component that integrates Internet Data Exchange (IDX) functionality into a real estate website. Since WordPress is the most used system for real estate websites – the IDX plugin often refers to a WordPress IDX plugin.

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IDX vendor

IDX vendor is a company that accesses the Multiple Listing Service (MLS) on behalf of a real estate agent, facilitating the integration of MLS listings onto the agent’s website. Vendors enable agents to display property listings while managing compliance with IDX standards and regulations.

What are the differences between MLS and IDX?

MLS stands for Multiple Listing Service

It is a particular database made and managed by real estate experts to assist their clients in searching, buying, and selling property. We have a complete guide: The Ultimate Guide: What is Multiple Listing Service ( MLS ) in Real Estate and How Does It Work?

IDX listings usually come from MLS Systems, which can serve one or multiple associations or boards. REALTORS associations or brokers might own these systems or operate independently. 

They can cover anything from a single city or county to large regions. For additional information about MLS® Systems, you can visit the National Association of REALTORS® website.

IDX (Internet Data Exchange)

 Is the policy that enables real estate agents to display MLS (Multiple Listing Service) data on their websites, making it easily accessible to potential buyers who visit their sites. 

Integrating IDX with each MLS helps agents expand their reach to a broader audience and offer valuable information to individuals interested in buying or selling real estate.

What are the technologies used for Internet Data Exchange (IDX) Technologies

Four main technologies are used to deliver IDX listings: RESO Web API, IDX Framing, FTP, and RETS. Each technique employs distinct approaches to accessing Multiple Listing Service (MLS) data and incorporating listings, bringing their advantages and limitations.


The RESO Web API represents the latest advancement in IDX technology. It employs an Application Programming Interface (API) to retrieve listings directly from an MLS and display or replicate them on a real estate agent’s website.


IDX framing (HTML iframe) involves displaying listings from external websites through a framed design feature on your site. It is a straightforward and quick way to integrate IDX, but it lacks Search Engine Optimization (SEO) capabilities and the possibility to create a custom web page.

FTP (File Transfer Protocol) 

FTP stores listings directly on your website server; however, the data transfer process of FTP can be cumbersome and inefficient. Complete file downloads are necessary for each synchronization, limiting the frequency of updates and potentially resulting in outdated information on your site.

RETS (Real Estate Transaction Standard)

RETS is an old standardized IDX technology that facilitates the exchange of real estate, but it is challenging to maintain. Newer technologies such as RESO Web API have replaced RETS nowadays for most MLS.

What are the Benefits of IDX for your business?

Despite the strict rules, IDX is very useful for real estate agents, and it’s a win-win for agents and people searching for homes.

  • Agents and brokers can show the best houses on their websites to attract buyers.
  • Buyers can see the newest homes on the market and trust that the information is correct.

Those who don’t use IDX might miss out on capturing leads or struggle to compete in the market. 

Here are a few other advantages of using IDX:

  • Let agents show more houses on their websites: Showing MLS listings helps agents attract clients searching for properties online, leading to more potential leads and sales.
  • MLS listings make the website seem more trustworthy: It shows potential clients that agents are reliable and have access to up-to-date property information.
  • Streamlined workflow: IDX’s newest technologies, like RESO WEB API, automate the process of updating websites with new listings, freeing up agents’ time to focus on other important tasks like marketing and client service.

Homebuyers frequently ask their agents to explain what IDX is and why it’s important for their property search. We have a more detailed article about What Are the Benefits and Advantages of Using Multiple Listings Service(MLS)

IDX Listing Display Options for Brokers and Agents

You don’t have to do anything when your MLS starts using the IDX program. The system assumes you agree to display your listings. 

If you prefer not to show your listings to others, you can inform the MLS that you’re withholding your consent. 

IDX listing – Website made with WPresidence Theme

Some MLSs require you to actively choose to participate, while others assume you’re in by default. Whether it’s “opt-in” or “opt-out” depends on your local MLS’s decision.

For brokers in the program, the following options are available for displaying IDX data on their website:

  • Download data from the MLS to create and manage a broker-owned website with compliant display pages.
  • Employ an external consultant or an approved third-party vendor to integrate IDX listings through an IDX Plugin.

Among these options, the most cost-effective is the first one, with MLS Import as a helpful plugin for downloading and syncing MLS data. Supported themes ensure the necessary real estate functionality and smooth operation.

Agents can also have IDX websites provided they adhere to specific guidelines:

  • The agent’s designated broker must be opted into the program.
  • The agent must obtain their broker’s consent and prominently display the brokerage brand and logo.

What are the Industry Rules for Using the IDX System?

The IDX platform has specific rules governed by the National Association of Realtors (NAR). Here, you can read the detailed guide on NAR’s IDX regulations.

While it can boost business, violating IDX rules can have serious consequences. Some activities that may lead to legal problems include:

  • IDX listings should only be used for IDX display.
  • If sellers don’t want property addresses online, agents should respect their wishes and not display them on IDX.
  • IDX displays can be based on location, price, property type, etc.
  • The MLS data should be updated every 12 hours.
  • NAR emphasizes that IDX displays cannot distribute MLS data to anyone else except as outlined in the policy.
  • Participants must identify their brokerage while showing IDX content with distinct colors and typeface.
  • Participants should be open to feedback about listing accuracy and correct any false information provided by the listing broker/agent, except for opinions or professional judgment.
  • Participants cannot share IDX listings with external parties outside the IDX exchange.
  • Participants cannot modify information to make listings more attractive.

Agents and realtors must follow these rules to uphold their professional integrity and reputation.

What happens if someone abuses IDX?

If someone misuses IDX, the MLS association will take appropriate action. Offenders will be notified and asked to correct the problem. Failure to comply can lead to disciplinary measures per MLS Rules and Regulations.

How to Get an Affordable IDX Real Estate Website?

Many real estate professionals are often curious about what IDX is and how it can enhance their online property listings.

Creating a real estate website on a budget can be challenging, especially for startups watching every penny. Professional site design can be costly, and ongoing maintenance increases over time.

The good news is that you can have a functional and attractive real estate website without a hefty budget. Choose MLSImport for your IDX website needs.

We have two advanced guides: Building a Successful MLS Real Estate Website: A Comprehensive Guide to MLS Integration and How We Created a WordPress MLS Website with 8,000 Listings.​

Utilizing WordPress, pre-built friendly themes with real estate functionality, and cost-effective IDX solutions like MLSImport can help you create a professional online presence without breaking the bank. Prioritize features that matter most to your business, and consider DIY options where feasible to save costs and ensure flexibility.

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IDX is pivotal in today’s real estate, connecting buyers and sellers in an era where 97% of homebuyers rely on the internet. Evolving from a Realtor-exclusive tool to a consumer resource, IDX streamlines MLS listing display, fostering collaboration among professionals.

Integration with MLS has transformed how property information is shared, empowering consumers and promoting Broker Reciprocity. Technological advancements like the RESO Web API enhance efficiency, emphasizing the importance of understanding IDX components.

For startups, affordability is crucial. Utilizing platforms like WordPress, cost-effective themes, and solutions like MLSImport enables a professional online presence without breaking the bank. 

IDX saves costs and lets agents showcase more properties, build client trust, and streamline workflow through automated updates.

In summary, as the real estate industry embraces digital transformation, adopting an affordable IDX solution is vital for staying competitive. The journey to a functional and budget-friendly real estate website begins with a strategic approach.


The views in this article are the author’s information provided is for general information only and should not be considered professional advice in real estate, legal, or accounting matters. Please consult your MLS providers for advice on certification, professional guidance, or legal procedures.


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