generated: '2026-07-26' method: searched source: - https://transport.reso.org/versioning/ - https://transport.reso.org/policy-changes/ - https://transport.reso.org/reso-rcp-process - https://transport.reso.org/ - https://github.com/RESOStandards/transport/blob/main/proposals/web-api-core.md - https://www.nar.realtor/handbook-on-multiple-listing-policy/operational-issues-section-12-real-estate-transaction-standards-rets-policy-statement-790 note: >- RESO's lifecycle is a STANDARDS lifecycle, not a service lifecycle. There is no uptime SLA and no status page because RESO runs no production data service; what it publishes instead is an explicit, dated versioning policy, a ratification process, a deprecation model and an expiring certification. That policy is unusually well documented for this catalog. versioning: scheme: semver docs: https://transport.reso.org/versioning/ rules: - MAJOR when making incompatible API changes - MINOR when adding functionality in a backward compatible manner - PATCH when making backward compatible bug fixes practice: >- Data Dictionary uses major and minor only in public form (1.7, 2.0, 2.1); patch-level changes are tracked internally. Transport specifications include the patch level (Web API Core 2.0.0) but only major and minor are used in practice. negotiation: - {condition: Older version not supported, response: HTTP 400 Bad Request} - {condition: Newer version than the server supports, response: HTTP 400 Bad Request} current_versions: - {standard: Web API Core, rcp: RCP-37, version: 2.1.0, ratified: '2023-12', url: 'https://transport.reso.org/proposals/web-api-core'} - {standard: Data Dictionary, rcp: RCP-36/40, version: '2.0', ratified: '2023-11', url: 'https://transport.reso.org/proposals/data-dictionary'} - {standard: Web API Add/Edit, rcp: RCP-10, version: 2.0.0, ratified: '2023-12', url: 'https://transport.reso.org/proposals/web-api-add-edit'} - {standard: EntityEvent Resource and Replication, rcp: RCP-27, version: 2.0.2, ratified: '2023-12', url: 'https://transport.reso.org/proposals/entity-events'} - {standard: Push Replication with Webhooks, rcp: RCP-28, version: 1.0.1, ratified: '2023-12', url: 'https://transport.reso.org/proposals/webhooks-push'} - {standard: Validation Expressions, rcp: RCP-19, version: 1.0.0, ratified: '2023-12', url: 'https://transport.reso.org/proposals/validation-expressions'} - {standard: RESO Common Format, rcp: RCP-25, version: '1.7', ratified: '2023-11', url: 'https://transport.reso.org/proposals/reso-common-format'} counts: {ratified_standards: 7, in_progress_proposals: 14} in_progress: - {rcp: RCP-22, name: Autofill Service, version: 1.0.0} - {rcp: RCP-35, name: Supporting Single Feeds, version: 1.0.0} - {rcp: RCP-42, name: Model and Field Resources, version: 1.0.0} - {rcp: RCP-43, name: Local Fields and Predictability, version: 1.0.0} - {rcp: RCP-44, name: Metadata Internationalization and Locale, version: 1.0.0} - {rcp: RCP-45, name: Legacy and Deprecated Data Elements, version: 1.0.0} - {rcp: RCP-47, name: RelatedLookup Resource, version: 1.0.0} - {rcp: RCP-48, name: Add/Edit with Media, version: 1.0.0} - {rcp: RCP-49, name: EntityEvent Subscriptions and Filtering, version: 1.0.0} - {rcp: RCP-50, name: Data Provenance, version: 1.0.0} - {rcp: RCP-51, name: DOM Increment, version: 1.0.0} - {rcp: RCP-52, name: Listing Advertisement, version: 1.0.0} - {rcp: RCP-53, name: Media Checksums, dated: '2025-05'} - {rcp: RCP-54, name: ULI Resolution Protocol, version: 0.1.0} ratification_process: docs: https://transport.reso.org/reso-rcp-process stages: - {step: 1, name: Proposal, detail: Submitted via GitHub Discussions with a business case and requirements.} - {step: 2, name: Draft & Review, detail: 'Transport Workgroup reviews the draft specification and testing rules. At least two vendor implementations are required.'} - {step: 3, name: Approval, detail: Approved by the Transport Workgroup and Certification once implementations are verified; testing tools are built.} - {step: 4, name: Ratification, detail: 'Major versions require ratification by the RESO Board of Directors. Minor versions may be approved by the Transport Workgroup without Board ratification.'} deprecation: policy_url: https://transport.reso.org/versioning/ policy_changes_url: https://transport.reso.org/policy-changes/ sunset_header: false model: >- Deprecation is expressed through the specification and the certification test suite, not through HTTP headers. Removing something from a RESO specification means RESO stops testing for it in certification; providers may keep serving it unless expressly forbidden (for example a disallowed synonym), so deprecation from the standard is not removal from the API. breaking_change_definition: - A standard field has a type change. - A disallowed synonym is added for a resource, field or lookup. - An existing enumerated field is closed, or items are removed from an existing closed enumeration. - Duplicate or replacement data elements are added. - New testing rules are added to existing data elements, including Fast Track mappings. breaking_changes_require: Ratification of a MAJOR version by the RESO Board of Directors. active_deprecation_notices: - target: OData Edm.EnumType lookups status: deprecating replacement: Edm.String lookups via the Lookup Resource (RCP-032) reason: >- Edm.EnumType usually requires knowledge of vendor-specific namespaces and does not allow human-friendly lookup names. source: https://transport.reso.org/proposals/web-api-core - target: Edm.EnumType with IsFlags=true (multi-value lookups) status: deprecating replacement: Collection(Edm.String) with the Lookup Resource reason: Strictly following OData limits IsFlags to 64 total values. source: https://transport.reso.org/proposals/web-api-core - target: RESO Commander (web-api-commander, Java) status: to-be-deprecated replacement: The RESO SDK (@reso-standards/* TypeScript packages) source: https://github.com/RESOStandards/web-api-commander - target: OpenID Connect support in the Web API status: removed removed_in: Web API 1.0.2 replacement: OAuth2 Bearer tokens and Client Credentials only source: https://transport.reso.org/proposals/web-api-core - target: RETS (Real Estate Transaction Standard) status: legacy replacement: RESO Web API note: RESO still hosts RETS support pages for legacy implementers. certification_lifecycle: effective: '2025-12' approved_by: RESO Board of Directors source: https://transport.reso.org/policy-changes/ rules: - RESO endorsements will expire after two years. - RESO will always certify on the latest minor version in a given major branch. - New testing rules on existing data elements are a MAJOR change; on new data elements, MINOR. - Fast Track suggestions will only be required in the next major version; providers get warnings first. - The RESO SDK version will be added to endorsements. - Data Dictionary and Transport Workgroups may approve MINOR Data Dictionary versions without Board ratification, and no breaking changes may be introduced in a minor version. adoption_mandate: body: National Association of REALTORS (NAR) instrument: Handbook on Multiple Listing Policy, Policy Statement 7.90 url: https://www.nar.realtor/handbook-on-multiple-listing-policy/operational-issues-section-12-real-estate-transaction-standards-rets-policy-statement-790 rule: >- MLS organizations owned and operated by associations of REALTORS "will keep current by implementing new releases of RESO Standards within one (1) year from ratification." effect: >- A ratification date is therefore also a compliance clock for several hundred MLSs - the tightest adoption cadence of any standard in this catalog. sla: published: false note: RESO operates no production data service, so it publishes no uptime target. status_page: published: false probes: - {url: 'https://status.reso.org', status: 000, note: DNS does not resolve} - {url: 'https://www.reso.org/status/', status: 404} - {url: 'https://reso.statuspage.io', status: 200, note: 'redirects to atlassian.com marketing - not a RESO status page'} tooling_lifecycle: detail: changelog/reso-changelog.yml deprecated_operations: []