In real estate, data sharing between MLSs, websites, and apps has evolved from RETS to the RESO Web API. Here’s why it matters:
- RETS: Introduced in 1999, RETS standardized real estate data sharing but relied on XML and batch processing. It worked well for older systems but struggled with real-time updates, scalability, and modern security needs.
- RESO Web API: Launched to replace RETS, it uses RESTful architecture, JSON formatting, and real-time data access. It improves security with OAuth, simplifies integration with standardized field names, and reduces costs by eliminating local database duplication.
Quick Comparison
| Feature | RETS | RESO Web API |
|---|---|---|
| Data Format | XML (verbose) | JSON (lightweight) |
| Processing | Batch, periodic sync | Real-time, on-demand |
| Security | Basic | OAuth, advanced encryption |
| Integration | Complex, manual | Simplified, standardized |
| Scalability | Limited | High |
| Support | Ended in 2018 | Actively maintained |
RESO Web API is now the industry standard, offering faster, more secure, and scalable solutions for real estate data integration. RETS, while still in use by some MLSs, is outdated and less efficient for modern needs.
"Web API: Opportunities, Challenges, and the Next Evolution of RE Data" – 2019 RESO Fall Conference
What is RETS
RETS (Real Estate Transaction Standard) was a game-changing protocol that streamlined the way property listing data was shared between Multiple Listing Services (MLS) and real estate platforms across the United States. It gave brokers, agents, and tech vendors a way to access and sync property listings more efficiently.
RETS History and Development
Introduced in 1999, RETS brought much-needed order to the chaos of earlier MLS data formats. Before RETS, incompatible formats and inconsistent sharing methods made integration a nightmare for anyone in the real estate industry.
By the early 2000s, RETS had become the go-to standard, powering many real estate websites and applications. It allowed agents to display properties from multiple MLSs on a single platform, which was a huge step forward for the industry. However, in June 2018, the Real Estate Standards Organization (RESO) officially ended support for RETS, encouraging users to switch to the RESO Web API. Despite its official retirement, many MLS providers still use RETS today, though the shift toward the RESO Web API is growing. Over time, RETS faced challenges in keeping up with modern scalability and real-time demands.
RETS Key Features
RETS operated using HTTP and XML protocols with a request-response model for data queries and transfers. This setup provided a standardized way for different systems to communicate effectively.
One of its standout features was batch processing, which allowed users to download large datasets at scheduled intervals instead of in real time. This was particularly useful for organizations with older systems that couldn’t handle real-time updates. RETS worked well with legacy infrastructure, making it a practical choice for many companies that hadn’t modernized.
Some MLS databases using RETS housed over 100 GB of listing data, showcasing its ability to handle massive amounts of property information. This made it a favorite for large brokerages and real estate websites needing comprehensive data coverage.
RETS Limitations
As technology evolved, RETS struggled to keep up with the growing demand for real-time data and modern integration methods. Its reliance on outdated technologies and rigid formats made it less effective in today’s fast-paced market.
Scalability became a major hurdle. RETS wasn’t built to handle the increasing volume of data or the need for frequent updates. Its batch processing approach, while once a strength, now leads to delays in updates. This means websites often display outdated property information – a problem modern APIs with real-time synchronization don’t have.
Integration with newer platforms, mobile apps, and cloud services is another weak spot for RETS. Its dependence on XML, a bulky and rigid format, makes it harder to adapt to modern technologies. Additionally, field names in RETS often vary across MLSs, making cross-MLS data integration unnecessarily complex.
Security is another area where RETS falls short. It offers only basic security features and lacks the robust authentication and encryption standards found in newer systems. On top of that, duplicating MLS databases on local servers adds to hosting costs and complicates data management.
For businesses still relying on RETS, tools like BatchData can help fill the gaps. These solutions offer enhanced data enrichment, bulk data delivery, and integration services, allowing organizations to make better decisions even when working within the limitations of legacy systems.
What is RESO Web API?
The RESO Web API represents the next step in real estate data integration, designed to replace the outdated RETS system with more efficient, modern technology. Created by the Real Estate Standards Organization (RESO), this API facilitates real-time, standardized data sharing between Multiple Listing Services (MLSs) and real estate technology platforms.
Using a RESTful architecture and JSON formatting, the RESO Web API addresses the limitations of RETS, such as scalability issues and delays in real-time data processing, while adhering to current web development standards.
How RESO Web API Came to Be
As technology advanced and businesses demanded quicker, more adaptable data access, RESO realized that incremental updates to RETS wouldn’t suffice. Instead, a complete redesign was needed. This shift gained momentum when RESO officially ended support for RETS, encouraging the real estate industry to embrace the Web API standard. The decision was informed by years of feedback from developers, brokers, and tech vendors who had struggled with RETS’ challenges, including poor scalability, lack of real-time updates, and difficulties integrating with modern platforms.
The RESO Web API was built to align with contemporary web practices, making it easier for the real estate sector to meet evolving user expectations.
Key Features of the RESO Web API
The RESO Web API is built on RESTful principles, employing standard HTTP methods and JSON for data formatting. This is a significant improvement over RETS, which relied on XML. JSON’s lightweight structure makes it easier for developers to process data efficiently. Real-time data access is another major advantage, enabling direct queries to MLS databases and eliminating the delays associated with batch processing in RETS.
The API also supports OData, a protocol that standardizes query structures across different MLS implementations, making integration smoother. Its scalability ensures it can handle large datasets and high transaction volumes without compromising performance. Furthermore, the API enforces compliance with the RESO Data Dictionary, which standardizes field names and data structures across MLSs, simplifying cross-platform integration.
These features collectively provide a robust framework that addresses the shortcomings of RETS.
Advantages of RESO Web API Over RETS
One of the most notable improvements is in security. The RESO Web API uses modern protocols like OAuth for secure authentication and advanced encryption to protect data during transmission. This addresses the security vulnerabilities that plagued RETS.
Integration is also far less complicated. The API offers well-documented endpoints, human-readable field names, and developer tools that make building and maintaining integrations much easier. Features like automated API key management and standardized query formats further simplify the onboarding process for new applications. The improved developer experience leads to faster development cycles, quicker product launches, and easier expansion into new markets. For instance, the Toronto Regional Real Estate Board (TRREB) transitioned from RETS to the RESO Web API to improve data accuracy, security, and third-party integrations, resulting in more streamlined workflows for its members.
Another significant benefit is cost efficiency. By eliminating the need for local database duplication and frequent batch updates, the RESO Web API reduces hosting and maintenance costs. MLSs that have adopted the API, such as those using platforms like Spark, report faster vendor onboarding and lower technical support demands.
Additionally, advanced tools like BatchData take full advantage of the RESO Web API. By accessing standardized, real-time property and contact data, these services offer features like data enrichment, skip tracing, and bulk data delivery, empowering real estate professionals with actionable insights and improved decision-making capabilities.
RETS vs RESO Web API: Side-by-Side Comparison
When comparing RETS and RESO Web API, the differences become clear – and they explain why the real estate industry has transitioned from the older RETS system to the more modern RESO Web API standard.
Feature Comparison Table
Here’s a closer look at how these two systems differ across key technical and functional areas:
| Feature | RETS | RESO Web API |
|---|---|---|
| Technology Stack | HTTP, XML | RESTful API, JSON, OData |
| Data Format | XML (verbose, rigid) | JSON (lightweight, flexible) |
| Scalability | Limited | High, designed for large datasets |
| Processing Type | Batch, periodic sync | Real-time, on-demand |
| Integration Complexity | High (manual, technical) | Low (modern, well-documented) |
| Security | Basic, less flexible | OAuth, modern encryption |
| Developer Experience | Steep learning curve, less documentation | Easier, more tools, better support |
| Field Standardization | Proprietary | RESO Data Dictionary, standardized |
| Industry Support | Deprecated (since June 2018) | Actively supported, industry standard |
| Cost | Higher (hosting, maintenance) | Lower (cloud-based, direct access) |
This table highlights the fundamental distinctions, which are further explained below.
One of the most noticeable differences lies in the technology each system uses. RETS relies on XML, a verbose and rigid data format that can slow down processing. On the other hand, the RESO Web API uses JSON, a more compact and flexible format that enables faster, smoother data transfers.
Another key difference is how data is processed. RETS operates on a batch download system, which can result in delays when updating information. In contrast, the RESO Web API offers real-time, on-demand access to MLS data, ensuring that users always have the most current information at their fingertips.
Cost and maintenance also set these systems apart. RETS requires local storage, frequent updates, and ongoing maintenance, all of which can drive up expenses. The RESO Web API eliminates these needs, offering direct, cloud-based access that significantly reduces costs.
Security is another area where the RESO Web API shines. RETS relies on basic authentication methods, which are considered outdated by today’s standards. The RESO Web API uses OAuth and modern encryption techniques, ensuring a much higher level of security.
For developers, the RESO Web API is a game-changer. RETS often demands specialized expertise and manual configuration for each MLS connection, making integrations time-consuming and complex. In contrast, the RESO Web API provides standardized endpoints, thorough documentation, and developer-friendly tools, simplifying the entire integration process. The inclusion of the RESO Data Dictionary further enhances consistency, making it easier to work across multiple MLS systems.
Advanced data platforms like BatchData take full advantage of the RESO Web API’s capabilities. They offer enhanced property search tools, real-time data updates, and efficient bulk data delivery. These modern solutions highlight the scalability and responsiveness that the RESO Web API enables – capabilities that RETS-based systems simply can’t match.
The industry’s move away from RETS, officially deprecated in June 2018, reflects more than just a preference for newer technology. It’s about meeting the growing demands for better performance, stronger security, and greater scalability in today’s real estate landscape.
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Compatibility and When to Use Each API
Choosing between RETS and RESO Web API depends on your system setup, data needs, and business objectives. Each API serves a unique purpose and works best in specific technology environments.
System Compatibility
RETS is designed for older MLS systems and relies on traditional data handling methods. It uses protocols like HTTP and XML, which typically require a dedicated server for batch data replication. With RETS, MLS data is periodically downloaded and stored locally, demanding technical expertise, manual updates, and ongoing maintenance to ensure compatibility with each MLS provider’s feed. Additionally, field names vary across MLSs, so custom mapping is necessary for each integration.
RESO Web API, on the other hand, aligns with modern technology standards. It uses RESTful architecture and JSON, making it a natural fit for today’s web and mobile applications. This API provides real-time access to MLS data without local replication, uses standardized field names via the RESO Data Dictionary, and integrates easily with cloud platforms and third-party services. Enhanced security features, such as OAuth and advanced encryption, also make it a better fit for enterprise-grade systems.
The technological divide between these APIs is clear. RETS demands specialized knowledge and manual configuration, while RESO Web API offers standardized endpoints that simplify integration across different MLS providers. These distinctions make it easier to choose the right API based on your organization’s specific needs.
Common Use Cases
Each API caters to distinct operational scenarios, depending on your requirements.
RETS is well-suited for batch data replication. It allows large datasets to be periodically downloaded and stored locally, which is useful for property search portals, CRM systems, or analytics platforms in environments where real-time data isn’t a priority. RETS remains relevant for MLS providers that haven’t transitioned to RESO Web API yet.
RESO Web API, on the other hand, is ideal for modern applications that require up-to-date information. It supports real-time property searches, instant data updates, and seamless integration with web and mobile platforms. Developers can make targeted, on-demand queries, reducing bandwidth and storage needs compared to batch replication. Typical use cases include dynamic property search portals, mobile apps with live listings, and integrations with advanced data solutions like BatchData for property and contact enrichment.
The way each API handles data access has a direct impact on performance. RETS relies on scheduled batch downloads, which can lead to data delays and higher storage demands. In contrast, RESO Web API offers real-time, on-demand access, enabling faster updates and reducing local storage needs. This results in better system performance, more accurate listings, and an improved experience for users of web and mobile apps.
Migration from RETS to RESO Web API
While RETS has its uses, transitioning to RESO Web API offers long-term benefits like real-time data access and enhanced security. However, the migration process comes with challenges, such as mapping legacy field names to the standardized RESO Data Dictionary, updating integration code, and maintaining data consistency during the transition. Organizations may also need to retrain staff, update security protocols, and work with MLS providers to obtain new API credentials. Legacy systems often require significant updates to fully utilize RESO Web API features.
Real-world migrations highlight both the challenges and rewards. Organizations transitioning from RETS to RESO Web API have faced hurdles like field mapping, system integration, and staff training. By adopting strategies such as parallel testing and phased rollouts, they’ve been able to improve data accuracy, reduce maintenance needs, and implement features like real-time property searches and stronger security measures.
To ensure a smooth migration, follow proven strategies. Conduct detailed data mapping, use automated tools for field translation, and run parallel systems to validate data integrity during the transition. Engage with MLS providers early, test in sandbox environments, and adopt incremental migration plans to minimize disruptions. Comprehensive documentation and staff training are essential for long-term success.
When deciding whether to stick with RETS or migrate to RESO Web API, assess your current system setup, the availability of RESO Web API support from your MLS provider, your need for real-time data, and long-term maintenance costs. RETS may still be suitable for legacy systems and batch processing needs, but for scalability, security, and future readiness, RESO Web API is the clear choice as the industry standard.
The urgency to migrate has grown since June 2018, when RESO officially ended support for RETS, pushing the industry toward RESO Web API. While many MLS providers still use RETS, more are announcing plans to fully transition to RESO Web API.
Impact on Real Estate Data Integration
The transition from RETS to the RESO Web API has reshaped how real estate data is integrated, making operations smoother and enabling smarter, data-driven decisions across various business processes.
Advanced Data Solutions and API Integration
Modern APIs have paved the way for advanced data platforms that were once challenging to implement with outdated systems. A great example of this is BatchData, a platform that uses these APIs to provide a suite of real estate services. These include property data enrichment, contact data verification, skip tracing, bulk data delivery, and phone verification – all integrated seamlessly.
Thanks to the RESO Web API’s standardized field names and data structures, platforms like BatchData can deliver real-time property searches, enriched listings, and bulk data directly into existing business systems. These technical improvements are creating clear advantages for different user groups.
Benefits for Different User Groups
Developers now have a much easier time integrating data. Unlike RETS, which required custom mapping for each MLS, the RESO Web API provides standardized endpoints across markets. This has sped up application development, reduced maintenance costs, and simplified scaling services to new regions.
Brokerages enjoy more accurate and consistent data. Without the need for local data replication, hosting costs and infrastructure demands have dropped, while data reliability has improved. This means fewer errors in property listings, leading to better client satisfaction. The standardized data formats also integrate more smoothly with CRM systems and marketing tools, simplifying agent workflows and communication with clients.
For larger brokerages and enterprise teams, compliance and security have seen significant improvements. Newer protocols like OAuth authentication and strong encryption ensure secure data handling, making it easier to meet regulatory requirements that were difficult to address with older systems.
Enterprise teams are using these APIs to drive advanced analytics and business intelligence. With consistent data structures, it’s easier to aggregate information from multiple MLSs for market analysis and strategic planning. By combining property data with external datasets – like demographic trends and market statistics – organizations can create smarter pricing strategies and investment recommendations.
The streamlined integration processes of modern APIs have also reduced the workload for IT teams. While RETS often required specialized expertise and manual configurations, today’s APIs come with better documentation and automated API key management. This means general development teams can handle integrations, allowing organizations to expand their data capabilities without needing to hire additional technical staff.
With real-time data access and standardized formats, real estate organizations can now use tools like automated valuation models, predictive analytics, and market analysis to make more informed decisions. These advancements are helping the industry leverage data for long-term growth and success.
Conclusion
The move from RETS to the RESO Web API marks a significant evolution in how real estate data is managed. While RETS served its purpose for years, its reliance on outdated XML architecture and batch processing made it less efficient. On the other hand, the RESO Web API offers real-time data access, standardized fields, and better security – all while cutting costs by eliminating the need for hosting massive databases exceeding 100 GB.
This shift isn’t just technical; it’s transformative for businesses. Developers now benefit from faster integrations and the ability to scale across multiple markets with ease. Here’s a quick recap of the key differences:
Main Points Summary
- RETS revolutionized automated real estate data exchange back in 1999, but it required duplicating entire databases. This led to higher hosting expenses and slower updates due to batch processing.
- RESO Web API leverages RESTful architecture and JSON formatting, allowing direct access to MLS databases without duplication. Since RETS support officially ended in June 2018, the industry has embraced this modern standard, complete with a Data Dictionary that ensures consistency across MLS systems.
- Modern APIs enable advanced services, such as property data enrichment and bulk delivery provided by companies like BatchData. With OAuth authentication and encryption, they also help organizations stay compliant with regulatory requirements.
This transition is more than just a technical upgrade – it’s a leap toward a more efficient, scalable, and secure future for real estate data management.
FAQs
What are the key benefits of using the RESO Web API compared to RETS for real estate data integration?
The RESO Web API brings several clear benefits when compared to the older RETS protocol for real estate data integration. For starters, it’s built on modern RESTful architecture, which simplifies implementation, maintenance, and scaling. This means smoother data handling, faster transfers, and better compatibility with today’s software tools.
Another big plus is its support for standardized data formats like JSON. JSON is not only widely used but also developer-friendly, making it easier to work with. On top of that, the RESO Web API provides real-time data access, ensuring property information is always up-to-date – an absolute must in the fast-moving world of real estate. These advantages position the RESO Web API as a smarter, more efficient option for handling real estate data.
What are the security and scalability benefits of transitioning from RETS to the RESO Web API for real estate data management?
The shift from RETS (Real Estate Transaction Standard) to the RESO Web API brings major improvements in security and scalability for managing real estate data. By using modern web standards like RESTful architecture and OAuth 2.0 for authentication, the RESO Web API offers a much stronger and safer framework for accessing and sharing information compared to the outdated RETS protocol.
When it comes to scalability, the RESO Web API is built to handle large volumes of data with ease, making it a perfect fit for today’s real estate applications that rely on real-time data access. Plus, its compatibility with various programming languages and tools simplifies integration, streamlining workflows and supporting the ever-changing demands of modern technology.
What are the potential challenges of migrating from RETS to the RESO Web API, and how can they be resolved?
Migrating from RETS to the RESO Web API comes with its fair share of hurdles. These can include compatibility mismatches, tricky data mapping, and the need for infrastructure updates. Since RETS is an older standard, it often doesn’t mesh seamlessly with the modern architecture and data formats of the RESO Web API. This can mean making significant changes to how existing workflows operate.
To tackle these obstacles, it’s crucial to start with a detailed analysis of your current systems to pinpoint areas where compatibility falls short. Leveraging reliable data mapping tools and collaborating with experienced integration partners can make the transition much more manageable. On top of that, training your team and testing the new API in a controlled setting can help smooth out the process and reduce disruptions to everyday operations.
