Reso Webhooks

generated: '2026-07-26'
method: searched
spec_type: Webhooks
asyncapi_published: false
source:
- https://github.com/RESOStandards/transport/blob/main/proposals/webhooks-push.md
- https://github.com/RESOStandards/transport/blob/main/proposals/entity-events.md
- https://transport.reso.org/proposals/webhooks-push
- https://transport.reso.org/proposals/entity-events
note: >-
  RESO publishes no AsyncAPI document (transport.reso.org/asyncapi.yaml returns 404) but it does
  ratify the real-estate sector's event contract, in two layers: EntityEvent (RCP-27), an append-only
  change log served as an ordinary OData resource, and Push Replication with Webhooks (RCP-28), which
  pushes those same events to a consumer endpoint over HTTP POST. The direction is inverted from the
  usual webhook artifact: the CONSUMER implements the receiving endpoint, and the MLS is the producer.
  RESO itself sends no webhooks - it specifies them.
standards:
- id: RCP-27
  name: EntityEvent Resource and Replication
  version: 2.0.2
  ratified: '2023-12'
  url: https://transport.reso.org/proposals/entity-events
  model: pull
  description: >-
    Change tracking and incremental replication using the EntityEvent resource - the interface of an
    append-only log. Consumers poll it and pick up the corresponding records from the provider API.
- id: RCP-28
  name: Push Replication Using Webhooks and the RESO EntityEvent Resource
  version: 1.0.1
  ratified: '2023-12'
  url: https://transport.reso.org/proposals/webhooks-push
  model: push
  description: >-
    Adds the ability to push events from the EntityEvent Resource using webhooks, so consumers do not
    have to poll continuously.
event_surface:
  trigger: >-
    When an (EntityEventSequenceNumeric, ResourceName, ResourceRecordKey) tuple has been published to
    the EntityEvent resource, providers MAY push that event to data consumers.
  transport: HTTP POST from producer to the consumer's endpoint
  payload_format: RESO Common Format (RCP-25), single-valued or multi-valued
  authentication: OAuth2 bearer tokens
  context_annotation: '"@reso.context": "urn:reso:metadata:2.0:resource:entityevent"'
  payload_fields:
  - {name: EntityEventSequence, description: Monotonic sequence number identifying the event}
  - {name: ResourceName, description: The Data Dictionary resource the event refers to}
  - {name: ResourceRecordKey, description: The key of the changed record}
  headers:
  - name: EntityEventSource
    direction: producer -> consumer
    required: false
    type: String(255)
    description: >-
      Optional consumer-assigned label identifying which feed a pushed batch belongs to (e.g.
      "IDX Feed 123"). The only RESO-defined correlation header.
  - name: Retry-After
    direction: consumer -> producer
    required: false
    description: >-
      Date or duration in seconds. The producer waits that long before resuming transfer. After some
      number of retries the producer MAY stop the flow; the consumer may then have to POST to the
      producer's endpoint to resume the feed.
requirements:
- Consumers MUST implement an API endpoint that can receive EntityEvents.
- Producers MUST use an HTTP POST request to the consumer's API with an EntityEvent payload and the given credentials.
- Providers SHOULD also host an EntityEvent Resource so consumers may replay events as needed.
polite_behavior:
  guidance: >-
    Consumers SHOULD accept and queue events rather than blocking and trying to process them as they
    arrive - especially while initializing a new replication feed, when there may be a large backlog.
  backpressure: Retry-After
compatibility: Data Dictionary 2.0+ and the JSON Web API.
pull_alternative:
  odata: 'GET <service-root>/EntityEvent?$filter=EntityEventSequence gt {n}&$orderby=EntityEventSequence'
  note: >-
    The EntityEvent resource is an ordinary Data Dictionary resource (see data-model/), so it is
    queryable with the same OData options as Property or Member, and reachable through the RESO MCP
    `query` tool.
in_progress:
- {rcp: RCP-49, name: EntityEvent Subscriptions and Filtering, version: 1.0.0, status: in review}
certification:
  endorsement: EntityEvent (RCP-027)
  scenarios: 9-12 depending on mode
  modes: [observe (read-only), full (canary writes)]
  tool: reso-cert entity-event
probes:
- {url: 'https://transport.reso.org/asyncapi.yaml', status: 404, date: '2026-07-26'}