ISO New England

ISO New England Hourlylmp API

24 path template(s) under /hourlylmp in the published ISO New England Web Services API v1.1 documentation.

Documentation GitHub OpenAPI

Operations 24

GET /hourlylmp/da/final Default resource #

GET /hourlylmp/da/final/current Get the current Final Hourly LMPs for Hub, Load Zones, and External Nodes #

GET /hourlylmp/da/final/current/all Get the current Final Hourly LMPs for all locations #

GET /hourlylmp/da/final/current/location/{locationId} Get the current Final Da Hourly LMPs for a given location #

GET /hourlylmp/da/final/day/latest Get the latest published day's DA Final Hourly LMPs for all locations #

GET /hourlylmp/da/final/day/{day} GET /hourlylmp/da/final/day/{day} #

GET /hourlylmp/da/final/day/{day}/hour/{sh} GET /hourlylmp/da/final/day/{day}/hour/{sh} #

GET /hourlylmp/da/final/day/{day}/location/{locationId} Get the current Final Da Hourly LMPs for a given location #

GET /hourlylmp/da/final/info Get the Service Info for Final Da Hourly LMPs #

GET /hourlylmp/rt/final Default resource #

GET /hourlylmp/rt/final/day/{day} GET /hourlylmp/rt/final/day/{day} #

GET /hourlylmp/rt/final/day/{day}/hour/{sh} GET /hourlylmp/rt/final/day/{day}/hour/{sh} #

GET /hourlylmp/rt/final/day/{day}/location/{locationId} Get the current Final RT Hourly LMPs for day for location #

GET /hourlylmp/rt/final/info Get the Service Info for Final Rt Hourly LMPs #

GET /hourlylmp/rt/prelim Default resource #

GET /hourlylmp/rt/prelim/current Get the current Prelim RT Hourly LMPs for Hub, Load Zones, and External Nodes #

GET /hourlylmp/rt/prelim/current/all Get the current Prelim RT Hourly LMPs for all locations #

GET /hourlylmp/rt/prelim/current/location/{locationId} Get the current Prelim RT Hourly LMPs for a given location #

GET /hourlylmp/rt/prelim/day/{day} Get the current Prelim RT Hourly LMPs for a given Date #

GET /hourlylmp/rt/prelim/day/{day}/hour/{sh} GET /hourlylmp/rt/prelim/day/{day}/hour/{sh} #

GET /hourlylmp/rt/prelim/day/{day}/location/{locationId} Get the current Prelim RT Hourly LMPs for a given location #

GET /hourlylmp/rt/prelim/info Get the Service Info for Prelim RT Hourly LMPs #

GET /hourlylmp/rt/prelim/previous Get the previous interval Prelim RT Hourly LMPs for Hub, Load Zones, and External Nodes #

GET /hourlylmp/rt/prelim/previous/all Get the previous interval Prelim RT Hourly LMPs for all locations #

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OpenAPI Specification

openapi: 3.2.0
info:
  title: ISO New England Web Services API v1.1 Hourlylmp API
  version: '1.1'
  description: RESTful interface to ISO New England energy and market data. This OpenAPI document was DERIVED by API Evangelist from ISO New England's own published, machine-generated Enunciate technical documentation at https://webservices.iso-ne.com/docs/v1.1/ and the two XML Schemas it publishes (ns0.xsd, ns1.xsd, saved verbatim under schemas/). ISO New England does not publish an OpenAPI definition; the only provider-published machine-readable description of the interface is a WADL at https://webservices.iso-ne.com/api/v1.1?_wadl&_type=xml, which sits behind the same HTTP Basic authentication as the API and returned HTTP 401 to anonymous probes. Every path, method, parameter, description, media type and schema in this document is copied from the provider's published sources; nothing was invented. Each operation carries x-evidence naming the exact documentation page it came from. All feeds are available in XML and JSON, selected by adding a .xml or .json extension to the request URL or by sending an Accept header of application/xml or application/json.
  contact:
    name: ISO New England Ask ISO
    url: https://askiso.iso-ne.com/s/
  x-provenance:
    method: derived
    derived_by: API Evangelist enrichment pipeline
    derived_on: '2026-07-27'
    sources:
    - https://webservices.iso-ne.com/docs/v1.1/
    - https://webservices.iso-ne.com/docs/v1.1/ns0.xsd
    - https://webservices.iso-ne.com/docs/v1.1/ns1.xsd
    - https://www.iso-ne.com/participate/support/web-services-data
    not_provider_published: true
    note: Derived from provider-published HTML documentation and XSDs. Not an ISO New England artifact.
servers:
- url: https://webservices.iso-ne.com/api/v1.1
  description: Production base path (HTTP Basic over SSL)
security:
- basicAuth: []
tags:
- name: hourlylmp
  description: 24 path template(s) under /hourlylmp in the published ISO New England Web Services API v1.1 documentation.
paths:
  /hourlylmp/da/final:
    get:
      operationId: getHourlylmpDaFinal
      summary: Default resource
      description: Default resource. Redirects to Final RT LMP Info.
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                description: Response payload is not described in the published documentation.
            application/json:
              schema:
                description: Response payload is not described in the published documentation.
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.html
        harvested: '2026-07-27'
  /hourlylmp/da/final/current:
    get:
      operationId: getHourlylmpDaFinalCurrent
      summary: Get the current Final Hourly LMPs for Hub, Load Zones, and External Nodes
      description: Get the current Final Hourly LMPs for Hub, Load Zones, and External Nodes.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Final Da Hourly Lmps.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.current.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
  /hourlylmp/da/final/current/all:
    get:
      operationId: getHourlylmpDaFinalCurrentAll
      summary: Get the current Final Hourly LMPs for all locations
      description: Get the current Final Hourly LMPs for all locations.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Final Da Hourly Lmps.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.current.all.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
  /hourlylmp/da/final/current/location/{locationId}:
    get:
      operationId: getHourlylmpDaFinalCurrentLocationByLocationId
      summary: Get the current Final Da Hourly LMPs for a given location
      description: Get the current Final Da Hourly LMPs for a given location.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Final Da Hourly LMP for the given location.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmp'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmp'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.current.location.locationId.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmp
      parameters:
      - name: locationId
        in: path
        required: true
        schema:
          type: string
        description: The location id
  /hourlylmp/da/final/day/latest:
    get:
      operationId: getHourlylmpDaFinalDayLatest
      summary: Get the latest published day's DA Final Hourly LMPs for all locations
      description: Get the latest published day's DA Final Hourly LMPs for all locations.
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.day.latest.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
  /hourlylmp/da/final/day/{day}:
    get:
      operationId: getHourlylmpDaFinalDayByDay
      summary: GET /hourlylmp/da/final/day/{day}
      description: (no documentation provided)
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.day.day.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
  /hourlylmp/da/final/day/{day}/hour/{sh}:
    get:
      operationId: getHourlylmpDaFinalDayByDayHourBySh
      summary: GET /hourlylmp/da/final/day/{day}/hour/{sh}
      description: (no documentation provided)
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.day.day.hour.sh.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
      - name: sh
        in: path
        required: true
        schema:
          type: string
  /hourlylmp/da/final/day/{day}/location/{locationId}:
    get:
      operationId: getHourlylmpDaFinalDayByDayLocationByLocationId
      summary: Get the current Final Da Hourly LMPs for a given location
      description: Get the current Final Da Hourly LMPs for a given location.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Final Da Hourly LMP for the given location.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.day.day.location.locationId.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
        description: The day to retrieve data for (YYYYMMDD)
      - name: locationId
        in: path
        required: true
        schema:
          type: string
        description: The location id
  /hourlylmp/da/final/info:
    get:
      operationId: getHourlylmpDaFinalInfo
      summary: Get the Service Info for Final Da Hourly LMPs
      description: Get the Service Info for Final Da Hourly LMPs.
      tags:
      - hourlylmp
      responses:
        '200':
          description: the ServiceInfoElement for Final Da Houry LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.da.final.info.html
        harvested: '2026-07-27'
      x-xml-element: ServiceInfo
  /hourlylmp/rt/final:
    get:
      operationId: getHourlylmpRtFinal
      summary: Default resource
      description: Default resource. Redirects to Final RT Hourly LMP Info.
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                description: Response payload is not described in the published documentation.
            application/json:
              schema:
                description: Response payload is not described in the published documentation.
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.final.html
        harvested: '2026-07-27'
  /hourlylmp/rt/final/day/{day}:
    get:
      operationId: getHourlylmpRtFinalDayByDay
      summary: GET /hourlylmp/rt/final/day/{day}
      description: (no documentation provided)
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.final.day.day.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
  /hourlylmp/rt/final/day/{day}/hour/{sh}:
    get:
      operationId: getHourlylmpRtFinalDayByDayHourBySh
      summary: GET /hourlylmp/rt/final/day/{day}/hour/{sh}
      description: (no documentation provided)
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.final.day.day.hour.sh.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
      - name: sh
        in: path
        required: true
        schema:
          type: string
  /hourlylmp/rt/final/day/{day}/location/{locationId}:
    get:
      operationId: getHourlylmpRtFinalDayByDayLocationByLocationId
      summary: 'Get the current Final RT Hourly LMPs for day for location '
      description: Get the current Final RT Hourly LMPs for day for location .
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Final RT Hourly LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.final.day.day.location.locationId.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
        description: The day to retrieve data for (YYYYMMDD)
      - name: locationId
        in: path
        required: true
        schema:
          type: string
        description: The location id
  /hourlylmp/rt/final/info:
    get:
      operationId: getHourlylmpRtFinalInfo
      summary: Get the Service Info for Final Rt Hourly LMPs
      description: Get the Service Info for Final Rt Hourly LMPs.
      tags:
      - hourlylmp
      responses:
        '200':
          description: the ServiceInfoElement for Five Minute LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.final.info.html
        harvested: '2026-07-27'
      x-xml-element: ServiceInfo
  /hourlylmp/rt/prelim:
    get:
      operationId: getHourlylmpRtPrelim
      summary: Default resource
      description: Default resource. Redirects to Prelim RT Hourly LMP Info.
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                description: Response payload is not described in the published documentation.
            application/json:
              schema:
                description: Response payload is not described in the published documentation.
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.html
        harvested: '2026-07-27'
  /hourlylmp/rt/prelim/current:
    get:
      operationId: getHourlylmpRtPrelimCurrent
      summary: Get the current Prelim RT Hourly LMPs for Hub, Load Zones, and External Nodes
      description: Get the current Prelim RT Hourly LMPs for Hub, Load Zones, and External Nodes.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Prelim RT Hourly LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.current.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
  /hourlylmp/rt/prelim/current/all:
    get:
      operationId: getHourlylmpRtPrelimCurrentAll
      summary: Get the current Prelim RT Hourly LMPs for all locations
      description: Get the current Prelim RT Hourly LMPs for all locations.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Prelim RT Hourly LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.current.all.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
  /hourlylmp/rt/prelim/current/location/{locationId}:
    get:
      operationId: getHourlylmpRtPrelimCurrentLocationByLocationId
      summary: Get the current Prelim RT Hourly LMPs for a given location
      description: Get the current Prelim RT Hourly LMPs for a given location.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpElement containing the current Prelim RT Hourly LMP for the given location.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmp'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmp'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.current.location.locationId.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmp
      parameters:
      - name: locationId
        in: path
        required: true
        schema:
          type: string
        description: The location id
  /hourlylmp/rt/prelim/day/{day}:
    get:
      operationId: getHourlylmpRtPrelimDayByDay
      summary: Get the current Prelim RT Hourly LMPs for a given Date
      description: Get the current Prelim RT Hourly LMPs for a given Date.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Prelim RT Hourly LMP for the given date .
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.day.day.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
        description: The day to retrieve data for (YYYYMMDD)
  /hourlylmp/rt/prelim/day/{day}/hour/{sh}:
    get:
      operationId: getHourlylmpRtPrelimDayByDayHourBySh
      summary: GET /hourlylmp/rt/prelim/day/{day}/hour/{sh}
      description: (no documentation provided)
      tags:
      - hourlylmp
      responses:
        '200':
          description: Successful response.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.day.day.hour.sh.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
      - name: sh
        in: path
        required: true
        schema:
          type: string
  /hourlylmp/rt/prelim/day/{day}/location/{locationId}:
    get:
      operationId: getHourlylmpRtPrelimDayByDayLocationByLocationId
      summary: Get the current Prelim RT Hourly LMPs for a given location
      description: Get the current Prelim RT Hourly LMPs for a given location.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the current Prelim RT Hourly LMP for the given date and location.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.day.day.location.locationId.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
        description: The day to retrieve data for (YYYYMMDD)
      - name: locationId
        in: path
        required: true
        schema:
          type: string
        description: The location id
  /hourlylmp/rt/prelim/info:
    get:
      operationId: getHourlylmpRtPrelimInfo
      summary: Get the Service Info for Prelim RT Hourly LMPs
      description: Get the Service Info for Prelim RT Hourly LMPs.
      tags:
      - hourlylmp
      responses:
        '200':
          description: the ServiceInfoElement for Prelim Rt Hourly LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.info.html
        harvested: '2026-07-27'
      x-xml-element: ServiceInfo
  /hourlylmp/rt/prelim/previous:
    get:
      operationId: getHourlylmpRtPrelimPrevious
      summary: Get the previous interval Prelim RT Hourly LMPs for Hub, Load Zones, and External Nodes
      description: Get the previous interval Prelim RT Hourly LMPs for Hub, Load Zones, and External Nodes.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the previous interval Prelim RT Hourly LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.previous.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
  /hourlylmp/rt/prelim/previous/all:
    get:
      operationId: getHourlylmpRtPrelimPreviousAll
      summary: Get the previous interval Prelim RT Hourly LMPs for all locations
      description: Get the previous interval Prelim RT Hourly LMPs for all locations.
      tags:
      - hourlylmp
      responses:
        '200':
          description: a HourlyLmpsElement containing the previous interval Prelim RT Hourly LMPs.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
            application/json:
              schema:
                $ref: '#/components/schemas/HourlyLmps'
        '401':
          description: Unauthorized - HTTP Basic credentials from an ISO Express account are required. Verified by anonymous probe on 2026-07-27.
      x-evidence:
        source: https://webservices.iso-ne.com/docs/v1.1/rest.hourlylmp.rt.prelim.previous.all.html
        harvested: '2026-07-27'
      x-xml-element: HourlyLmps
components:
  schemas:
    LocationRef:
      type: object
      properties:
        $:
          type: string
          description: Element text value (serialized as "$" in the JSON representation, per observed API responses).
        '@LocId':
          type: integer
        '@LocType':
          type: string
          enum:
          - NETWORK AREA
          - LOAD ZONE
          - NETWORK NODE
          - HUB
          - HUB NODE
          - RELIABILITY REGION
          - EXT. NODE
          - RESERVE ZONE
          - SYSTEM
          - INT. AREA
          - EXT. AREA
          - DISPATCH ZONE
          - CAPACITY ZONE
          - DRRAZ
          - DRR AGGREGATION ZONE
      required:
      - '@LocId'
      x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_LocationRef
    HourlyLmp:
      $ref: '#/components/schemas/Lmp'
      x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_HourlyLmp
    ServiceInfo:
      type: object
      properties:
        LatestBeginDate:
          type: string
          format: date-time
        CreationDate:
          type: string
          format: date-time
      required:
      - LatestBeginDate
      - CreationDate
      x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_ServiceInfo
    HourlyLmps:
      type: object
      properties:
        HourlyLmp:
          type: array
          items:
            $ref: '#/components/schemas/HourlyLmp'
      x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_HourlyLmps
    Lmp:
      type: object
      properties:
        BeginDate:
          type: string
          format: date-time
        Location:
          $ref: '#/components/schemas/LocationRef'
        LmpTotal:
          type: number
        EnergyComponent:
          type: number
        CongestionComponent:
          type: number
        LossComponent:
          type: number
      required:
      - BeginDate
      - Location
      x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_Lmp
  securitySchemes:
    basicAuth:
      type: http
      scheme: basic
      description: HTTP Basic Authentication over SSL. Credentials come from a free, self-serve ISO Express account; ISO New England states that ISO Express account holders are automatically granted access to the public data feeds. See https://www.iso-ne.com/participate/applications-status-changes/access-software-systems

ISO New England Hourlylmp API

Operations 24

Documentation

Specifications

Schemas & Data

Other Resources