RESO Standards: A Practical Advantage for Real Estate Businesses

Why RESO Standards Matter

For years, real estate data lacked consistency – every MLS operated on its own terms, making integrations costly, slow, and hard to scale for tech companies and brokerages alike.

The Real Estate Standards Organization (RESO) was created to fix that fragmentation, giving real estate a shared data language and a modern way to move information. Its standards are now powering a quiet but transformative shift across the entire ecosystem – from MLSs and brokerages to startups and data platforms.

Overview of RESO Data Dictionary and Web API

RESO’s two cornerstone standards are:

• RESO Data Dictionary: A universal schema for structuring real estate data – essentially, a shared vocabulary for everything from property types and listing statuses to features and measurements. It defines standard field names, accepted values, and relationships so that everyone speaks the same data language.
  
• RESO Web API: A modern, RESTful data exchange protocol that replaces the older RETS format. Built on widely used web standards like OData and JSON, the RESO Web API makes it easier for developers to build and scale applications that connect to MLS systems – without custom connectors or legacy baggage.
  

Together, these standards simplify integrations, improve data consistency, and open up the industry to faster, cheaper innovation.

The Industry Push Toward Standardization

Standardization isn't just a nice-to-have anymore – it's a mandate. In 2016, the National Association of REALTORS® required MLSs to implement RESO’s Data Dictionary and Web API, accelerating adoption across the country. Today, over 500 MLSs are RESO certified, and over 90% offer Web API feeds. Brokerages, tech vendors, and data platforms have followed suit.

This push isn't just about compliance. It’s about survival in an industry that’s rapidly modernizing. With standardized data, companies can:

• Expand into new markets faster
• Reduce development and support costs
• Offer better, more consistent tools to agents and consumers
• Innovate with less friction and more speed
  
  

In short, RESO standards are the new baseline – and the businesses that embrace them through innovative Real Estate Software Development are the ones best positioned to lead the next era of real estate technology.

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Notable Business Impact Cases

While RESO standards are now widespread, their true value shines through in real-world business outcomes. Across the industry, companies are reporting faster integrations, lower costs, greater flexibility, and accelerated innovation after implementing the RESO Data Dictionary and Web API. Here are three standout examples:

Case 1: myTheo – Scaling Faster into New Markets

myTheo is a real estate tech startup offering tools for agents and brokerages to manage listings, clients, and deals. As it looked to grow into larger markets, it ran into a major barrier: data fragmentation. Every MLS (Multiple Listing Service – a regional database of real estate listings) had its own format, structure, and rules. Integrating into each one took weeks of custom work.

Two of the biggest targets – CRMLS (California Regional MLS, the largest MLS in the U.S. with over 100,000 users) and MRED (Midwest Real Estate Data, serving the Chicagoland area) – each had massive datasets and strict requirements.

To scale faster, myTheo adopted RESO standards early – specifically the RESO Data Dictionary (a standard set of field names and values for property data) and the RESO Web API (a modern, RESTful way to exchange data).

The result: Launch time in new markets dropped from nearly two months to just a few weeks. With a standardized approach, integrations became repeatable, onboarding got smoother, and MLS partnerships strengthened. For a startup in growth mode, RESO made expansion predictable and scalable.

Case 2: Homes.com – Turning Data Chaos into Efficiency

Another strong example comes from Homes.com, one of the largest national portals. That means pulling in listing data from hundreds of different MLSs – each with its own quirks. Managing these feeds wasn’t just time-consuming – it was resource-draining.

Before adopting RESO standards, building or updating an MLS feed could take 25 hours or more. The team was constantly translating formats, remapping fields, and dealing with inconsistencies.

By aligning with the RESO Data Dictionary and Web API, Homes.com standardized how it handled all incoming data. Instead of reinventing the process each time, they created a repeatable pipeline.

The impact was dramatic: Development time dropped to 16 hours per feed, and in many cases, just 2 hours with the Web API. That kind of efficiency meant lower costs, fewer errors, and more time for product innovation. It also set a blueprint for how other large platforms could operate at scale using RESO.

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Case 3: Doorify MLS – Building a Flexible, Future-Ready Platform

Doorify MLS, previously known as Triangle MLS, serves real estate professionals in North Carolina. Like many MLSs, it operated on a legacy platform that limited flexibility. Adding new features or switching vendors meant costly, time-consuming projects.

Doorify decided to modernize – but instead of locking into another single-vendor platform, they chose a standards-first approach. By building on the RESO Data Dictionary and Web API, they created a modular architecture where tools and interfaces could be swapped in and out without disrupting the system.

This gave them full control over their ecosystem – brokers and agents could use the best tech available, not just whatever the platform provider offered. And Doorify could innovate without waiting on a vendor roadmap.

In short: RESO gave them flexibility, speed, and leverage. It turned their MLS from a closed system into an open platform for growth.

Technology Innovation Trends Around RESO Standards

RESO standards are moving faster than ever to meet the real-world demands of brokers, MLSs, and tech companies.

One major shift is in the RESO Web API itself. Originally designed just for pulling data, it now supports full write operations. Thanks to the new Web API Add/Edit endorsement, brokers can push new listings, update price changes, and manage properties directly from their own platforms  –  no more depending on clunky proprietary interfaces. Organizations like the Real Estate Board of New York (REBNY) were first out of the gate, rolling out full Add/Edit functionality through the RESO API in 2023. It’s a practical step toward giving brokers a true "front-end of choice", letting them control listings through the tools they already use. More MLSs and vendors are following fast.

Validation is getting smarter too. Alongside Add/Edit, RESO introduced Validation Expressions  –  machine-readable business rules baked into the API  –  so platforms can automatically enforce clean, accurate data inputs (think: no more listings accidentally posted with a $0 price tag).

Real-time data updates are another leap forward. With the new EntityEvent/Webhooks endorsement, MLSs can instantly notify partners when data changes, rather than forcing vendors to keep polling for updates. It’s faster, lighter, and more efficient  –  exactly what modern software demands.

Meanwhile, RESO’s innovation engine keeps expanding. The launch of the RESO Common Format (RCF) in 2024 makes it possible to share real estate data cleanly across different systems, even if they’re not using the Web API. Early adopters like Canada’s Municipal Property Assessment Corporation (MPAC) are proof: RESO standards are breaking out of the MLS world into government and broader real estate ecosystems.

The RESO Data Dictionary also continues to evolve. New fields like CurrentPrice and expanded support for multi-family and building-level attributes show how the standard is adapting to the increasing complexity of the market. Standardizing how photos, videos, and floor plans are handled is next  –  something brokers and vendors have been asking for, and RESO is already building with the upcoming Add/Edit with Media update.

A big focus is interoperability through unique identifiers. RESO is pushing out standards like the Universal Parcel Identifier (UPI), the Unique Licensee Identifier (ULI), and the Unique Organization Identifier (UOI). These IDs will make it much easier to track properties, agents, and brokerages across MLSs, markets, and software platforms  –  no more patchwork matching or duplicate records. It’s all about frictionless data flow in a business where speed and accuracy make a real difference.

And it doesn’t stop there. As AI moves deeper into real estate, RESO is keeping pace by building standards that AI tools can rely on  –  from flagging AI-generated images to creating consistent descriptors for 3D tours and property features. RESO also invests in analytics tools that help organizations measure how closely they align with industry standards, giving leaders better insight into their data quality and competitive position.

Bottom line: RESO is future-proofing real estate data. The technology foundation it’s building  –  with real-time APIs, full data edit capabilities, clean interoperability, and AI-readiness  –  is setting the stage for faster, smarter, and more connected real estate businesses.

Conclusion

RESO standards have become a necessary part of doing business in real estate. They simplify data management, reduce development costs, and make scaling and innovating across markets easier.

As the industry continues to modernize, companies that align with RESO standards will be better positioned to operate efficiently and compete effectively. Standardization is part of running a smarter, more sustainable business.

FAQ: RESO Data Dictionary & RESO Web API Standards

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