openapi: 3.2.0
info:
  title: ISO New England Web Services API v1.1 Genfuelmix 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: genfuelmix
  description: 6 path template(s) under /genfuelmix in the published ISO New England Web Services API v1.1 documentation.
paths:
  /genfuelmix:
    get:
      operationId: getGenfuelmix
      summary: Default resource
      description: Default resource. Redirects to Gen Fuel Mix Info .
      tags:
      - genfuelmix
      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.genfuelmix.html
        harvested: '2026-07-27'
  /genfuelmix/current:
    get:
      operationId: getGenfuelmixCurrent
      summary: Get the current Gen Fuel Mixes
      description: Get the current Gen Fuel Mixes.
      tags:
      - genfuelmix
      responses:
        '200':
          description: a GenFuelMixesElement containing the current Gen Fuel Mixes.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
            application/json:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
              example:
                GenFuelMixes:
                  GenFuelMix:
                  - MarginalFlag: N
                    GenMw: 228
                    FuelCategoryRollup: Batteries
                    FuelCategory: Batteries
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: Y
                    GenMw: 1841
                    FuelCategoryRollup: Hydro
                    FuelCategory: Hydro
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: Y
                    GenMw: 10061
                    FuelCategoryRollup: Natural Gas
                    FuelCategory: Natural Gas
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: N
                    GenMw: 3336
                    FuelCategoryRollup: Nuclear
                    FuelCategory: Nuclear
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: N
                    GenMw: 10
                    FuelCategoryRollup: Other
                    FuelCategory: Other
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: N
                    GenMw: 23
                    FuelCategoryRollup: Renewables
                    FuelCategory: Landfill Gas
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: N
                    GenMw: 306
                    FuelCategoryRollup: Renewables
                    FuelCategory: Refuse
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: N
                    GenMw: 473
                    FuelCategoryRollup: Renewables
                    FuelCategory: Solar
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: N
                    GenMw: 91
                    FuelCategoryRollup: Renewables
                    FuelCategory: Wind
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
                  - MarginalFlag: N
                    GenMw: 281
                    FuelCategoryRollup: Renewables
                    FuelCategory: Wood
                    BeginDate: '2026-07-27T17:23:19.000-04:00'
        '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.genfuelmix.current.html
        harvested: '2026-07-27'
      x-xml-element: GenFuelMixes
      x-example-evidence:
        source: https://www.iso-ne.com/ws/wsclient (public ISO Express dashboard proxy, anonymous POST)
        observed: '2026-07-27'
        note: Real response payload observed anonymously through the public dashboard proxy; the proxy envelope and its _url key were removed.
  /genfuelmix/current/fuelCategoryRollup/{fuelCategoryRollup}:
    get:
      operationId: getGenfuelmixCurrentFuelCategoryRollupByFuelCategoryRollup
      summary: Get the current Gen Fuel Mixes for a given fuelCategoryRollup
      description: Get the current Gen Fuel Mixes for a given fuelCategoryRollup.
      tags:
      - genfuelmix
      responses:
        '200':
          description: a GenFuelMixesElement containing the current Gen Fuel Mixes for the given fuel category.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
            application/json:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
        '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.genfuelmix.current.fuelCategoryRollup.fuelCategoryRollup.html
        harvested: '2026-07-27'
      x-xml-element: GenFuelMixes
      parameters:
      - name: fuelCategoryRollup
        in: path
        required: true
        schema:
          type: string
        description: The fuel category
  /genfuelmix/day/{day}:
    get:
      operationId: getGenfuelmixDayByDay
      summary: Get an entire days Gen Fuel Mix for given day
      description: Get an entire days Gen Fuel Mix for given day. Only the past [?] days are supported.
      tags:
      - genfuelmix
      responses:
        '200':
          description: a GenFuelMixesElement containing the Gen Fuel Mix.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
            application/json:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
        '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.genfuelmix.day.day.html
        harvested: '2026-07-27'
      x-xml-element: GenFuelMixes
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
        description: The day to retrieve data for (YYYYMMDD)
  /genfuelmix/day/{day}/fuelCategoryRollup/{fuelCategoryRollup}:
    get:
      operationId: getGenfuelmixDayByDayFuelCategoryRollupByFuelCategoryRollup
      summary: Get an entire days Gen Fuel Mix for given fuelCategoryRollup
      description: Get an entire days Gen Fuel Mix for given fuelCategoryRollup. Only the past [?] days are supported.
      tags:
      - genfuelmix
      responses:
        '200':
          description: a GenFuelMixesElement containing the Gen Fuel Mix.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
            application/json:
              schema:
                $ref: '#/components/schemas/GenFuelMixes'
        '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.genfuelmix.day.day.fuelCategoryRollup.fuelCategoryRollup.html
        harvested: '2026-07-27'
      x-xml-element: GenFuelMixes
      parameters:
      - name: day
        in: path
        required: true
        schema:
          type: string
        description: The day to retrieve data for (YYYYMMDD)
      - name: fuelCategoryRollup
        in: path
        required: true
        schema:
          type: string
        description: The fuel category
  /genfuelmix/info:
    get:
      operationId: getGenfuelmixInfo
      summary: Get the Service Info for Gen Fuel Mix
      description: Get the Service Info for Gen Fuel Mix.
      tags:
      - genfuelmix
      responses:
        '200':
          description: the ServiceInfoElement for Gen Fuel Mix.
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
            application/json:
              schema:
                $ref: '#/components/schemas/ServiceInfo'
              example:
                ServiceInfo:
                  CreationDate: '2026-07-27T17:23:21.000-04:00'
                  LatestBeginDate: '2026-07-27T17:23:19.000-04:00'
        '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.genfuelmix.info.html
        harvested: '2026-07-27'
      x-xml-element: ServiceInfo
      x-example-evidence:
        source: https://www.iso-ne.com/ws/wsclient (public ISO Express dashboard proxy, anonymous POST)
        observed: '2026-07-27'
        note: Real response payload observed anonymously through the public dashboard proxy; the proxy envelope and its _url key were removed.
components:
  schemas:
    GenFuelMix:
      type: object
      properties:
        BeginDate:
          type: string
          format: date-time
        GenMw:
          type: number
        FuelCategoryRollup:
          type: string
        FuelCategory:
          type: string
        MarginalFlag:
          type: string
          enum:
          - Y
          - N
          - '-'
      required:
      - BeginDate
      - GenMw
      - FuelCategoryRollup
      x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_GenFuelMix
    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
    GenFuelMixes:
      type: object
      properties:
        GenFuelMix:
          type: array
          items:
            $ref: '#/components/schemas/GenFuelMix'
      x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_GenFuelMixes
  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