Chetu – Custom Software Development CompanySearch blackphone blackcross black

IDX for Website Success: Iframe, FTP, or RETS?

By: Paul Bracht


The real estate industry relies on information exchange between the multiple listing service, or MLS, and real estate professionals' websites. This transfer occurs using software called IDX that was developed to facilitate cost-effective listing sharing between real estate parties. Short for internet data exchange, IDX allows real estate agents and brokers to receive and display listing data from their subscribed MLSs.

Several protocols exist to support IDX integration with agent websites. The main options are iframe, FTP, and RETS. Each has its pros and cons for agents and brokers to consider, as described below.

What is an iframe MLS Search?

An iframe is an HTML element used for embedding documents or search windows on websites. It displays data from other sources, and the content remains at the source. In the MLS listings case, the idx iframe displays an MLS search window on the real estate agent's website.

One benefit of the iframe approach is that the website user searches the host MLS database via the iframe window, so the listing results are current. Further, MLSs often offer this search capability to subscribing agents for free. The MLS iframe is also easy to implement, requiring only some HTML encoding.

For real estate professionals leveraging a web audience in their marketing strategies, online visibility and branding are top considerations. One drawback of the MLS iframe is that it adds no value for SEO. The content won't show in online search results because there is no data exchange between the iframe and MLS providers.

Consequently, search engines may rank iframe websites lower than competitors leveraging data exchanges. Buyers searching for listings are less likely to see iframe websites in their results, and those agents potentially lose leads.

Another consideration is that the agent can't design an IDX iframe to match branding or a website's look and feel. The iframe has a boxy, framed look that is functional but may not deliver the desired user experience. Further, the agent cannot customize the content as it resides in the MLS database.

Iframe pros:

Iframe cons:

What is an iframe MLS Search?

What is FTP?

A second IDX option is FTP or file transfer protocol. Widely used for decades, FTP is a reliable protocol for transferring files across a network. The MLS provider transfers listing data at scheduled intervals to the client website for display. The transfer occurs in one large file, commonly every 12 hours.

FTP is SEO-friendly as the agent site hosts the downloaded listing data. However, due to the synchronization lag time of at least several hours, SEO is not as robust as for sites exchanging data more frequently. In a dynamic market, potential buyers may not see the latest listings in an FTP display if the refresh is several hours old.

FTP feeds may not include all of the MLS fields available with an iframe search or a RETS feed. Agents should evaluate the content offered by each type for the MLSs they use.

Another consideration is that FTP feeds download listing information in a single file, which can be quite large and potentially slow to transfer. There are no incremental updates, and all MLS data is resent every time. The MLS provider may limit data sent due to file size constraints.

FTP also comes with startup costs as it lacks standards specific to the real estate industry. Each website must be customized to implement FTP for IDX integration, which can entail time and expense.

FTP pros:

FTP cons:

What is RETS?

RETS is the acronym for real estate transaction standard, a protocol developed specifically for the real estate field. The National Association of Realtors created it in 1999 to simplify data transfer for the many MLS services by providing a standardized framework. Every American MLS service offers RETS.

RETS is easy to implement, offers numerous search fields, and is usually updated hourly. It only sends incremental updates, which are smaller and faster than the FTP complete listing transfers. RETS content also benefits SEO due to frequent data exchanges that contain fresh content. As with FTP, the real estate website hosts the information.

One caveat is that the RETS feed sends raw data that needs additional software or human expertise to interpret it. Agents and brokers often use third-party vendors who translate the data for display and offer related website features and functionality.

Although still universally used, RETS is deprecated in favor of the new Web API standard. The Real Estate Standards Organization, RESO, launched Web API to leverage existing open design standards and tools. It aims to facilitate interoperability and allow easy access from websites, mobile, and social media.

RETS pros:

RETS cons:

Choosing an IDX Solution

To market effectively online, real estate agents rely on timely and user-friendly MLS information via IDX. An iframe is a simple, no-frills solution that lets users directly search the MLS but lacks SEO and customizability. An FTP feed supports SEO but has implementation overhead and data synchronization limitations.

As the current standard, a RETS feed offers flexibility and frequent updates but requires third-party services to package it into a useable form. As this standard evolves to RESO Web API, real estate professionals can expect even more robust support for their dynamic industry.


Chetu, Inc. does not affect the opinion of this article. Any mention of specific names for software, companies or individuals does not constitute an endorsement from either party unless otherwise specified. All case studies and blogs are written with the full cooperation, knowledge and participation of the individuals mentioned. This blog should not be construed as legal advice.

Chetu was incorporated in 2000 and is headquartered in Florida. We deliver World-Class Software Development Solutions serving entrepreneurs to Fortune 500 clients. Our services include process and systems design, package implementation, custom development, business intelligence and reporting, systems integration, as well as testing, maintenance and support. Chetu's expertise spans across the entire IT spectrum.

- See more at:

Suggested Reading

Access & Promote Listings Online with Real Estate MLS, IDX, and RETS Integration

Access & Promote Listings Online with Real Estate MLS, IDX, and RETS Integration

Read More
Benefits of RETS Feeds in Real Estate

Benefits of RETS Feeds in Real Estate

Read More
Three Tips for Your Real Estate Web Portal

Three Tips for Your Real Estate Web Portal

Read More

Privacy Policy | Legal Policy | Careers | Sitemap | Referral | Contact Us

Copyright © 2000-2024 Chetu Inc. All Rights Reserved.

Button to scroll to top

By continuing to use this website, you agree to our cookie policy. GOT IT