RESO (Real Estate Standards Organization)
RESO, the Real Estate Standards Organization, is the United States industry body that writes and certifies the machine-readable contract for residential real estate data. It publishes the RESO Data Dictionary (the field, enumeration and lookup vocabulary) and the RESO Web API (an OData 4.0/4.01 profile, Web API Core 2.0.0 ratified Jan 2021 and 2.1.0 ratified Dec 2023), plus the RESO Common Format, EntityEvent replication, Push Replication with Webhooks, Validation Expressions and the URN-based Universal Parcel Identifier (UPI). NAR Policy Statement 7.90 requires MLSs owned and operated by associations of REALTORS to implement the Data Dictionary and the Web API and to adopt new releases within one year of ratification, which makes this the only mandated machine-readable API contract in the API Evangelist sector study that is imposed by an industry body rather than a regulator. RESO itself operates no production API and holds no listing data: it certifies other people's servers. Its specifications, reference OData EDMX metadata and Data Dictionary JSON are freely and anonymously downloadable from transport.reso.org and the RESOStandards GitHub organization (a EULA click-through wraps the reso.org copies), and the certification directory at reso.org/certificates and certification.reso.org is public without login. Reachability is the separate fact: a RESO-certified endpoint is run by a local MLS, and credentials for it are issued only after a data licence with that MLS is signed, so certification here means conformance, never public access.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles RESO (Real Estate Standards Organization) the way a machine reads it — 9 machine-readable artifacts across 2 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — RESO (Real Estate Standards Organization) scores 46.8/100 (developing), with a separate agent-readiness read of 32/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-08 · rubric v0.20.0
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title="RESO (Real Estate Standards Organization) on API Evangelist — API profile and Kin Score">
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How we profile RESO (Real Estate Standards Organization)
Each block below is one kind of artifact we hold for RESO (Real Estate Standards Organization). For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 2
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
RESO Web API
The RESO Web API is the ratified transport standard for real estate data, defined as a profile of OData 4.0/4.01 (Web API Core 2.0.0 and 2.1.0). Servers MUST expose an OData XML...
RESO Cloud MCP Server
The RESO Cloud MCP Server is the one production API endpoint RESO itself operates. It speaks the Model Context Protocol over Streamable HTTP at https://services.reso.org/mcp and...
Open Collections 3
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
MCP Servers 1
Model Context Protocol servers expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.
Model Context Protocol servers that expose these APIs to AI agents.
Event Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Reso Webhooks
ASYNCAPISecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Resources
Every other property we hold for RESO (Real Estate Standards Organization) — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 4
Portal, sign-up, and the first successful call
Documentation 5
Reference material describing how the API behaves
Agent Surfaces 5
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 7
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 7 ·
Build 5
SDKs, sample code, and the tooling you integrate with
Access & Security 6
Authentication, authorization, and security posture
Operate 8
Status, limits, changes, and where to get help
Scroll within the panel for all 8 ·
Commercial 2
Pricing, plans, and the legal terms of use
Company 4
The organization behind the API
Other 6
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/reso · machine-readable index on apis.io
This is an independent, third-party profile of RESO (Real Estate Standards Organization), published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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