openapi: 3.2.0 info: title: ISO New England Web Services API v1.1 Dayaheadconstraints 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: dayaheadconstraints description: 4 path template(s) under /dayaheadconstraints in the published ISO New England Web Services API v1.1 documentation. paths: /dayaheadconstraints: get: operationId: getDayaheadconstraints summary: Default resource description: Default resource. Redirects to Day Ahead Constraints Info. tags: - dayaheadconstraints 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.dayaheadconstraints.html harvested: '2026-07-27' /dayaheadconstraints/current: get: operationId: getDayaheadconstraintsCurrent summary: 'Get the current Day Ahead Constraints ' description: Get the current Day Ahead Constraints . tags: - dayaheadconstraints responses: '200': description: a DayAheadConstraintsElement containing the current Day Ahead Constraints. content: application/xml: schema: $ref: '#/components/schemas/DayAheadConstraints' application/json: schema: $ref: '#/components/schemas/DayAheadConstraints' example: DayAheadConstraints: DayAheadConstraint: - ConstraintName: MIS ContingencyName: Interface MarginalValue: -8.69 BeginDate: '2026-07-27T17:00:00.000-04:00' InterfaceFlag: Y '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.dayaheadconstraints.current.html harvested: '2026-07-27' x-xml-element: DayAheadConstraints 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. /dayaheadconstraints/day/{day}: get: operationId: getDayaheadconstraintsDayByDay summary: Get Day Ahead Constrains for the day description: Get Day Ahead Constrains for the day. tags: - dayaheadconstraints responses: '200': description: a DayAheadConstraintsElement containing the Day Ahead Constraints. content: application/xml: schema: $ref: '#/components/schemas/DayAheadConstraints' application/json: schema: $ref: '#/components/schemas/DayAheadConstraints' '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.dayaheadconstraints.day.day.html harvested: '2026-07-27' x-xml-element: DayAheadConstraints parameters: - name: day in: path required: true schema: type: string description: The day to retrieve data for (YYYYMMDD) /dayaheadconstraints/info: get: operationId: getDayaheadconstraintsInfo summary: Get the Service Info for Day Ahead Constraints description: Get the Service Info for Day Ahead Constraints. tags: - dayaheadconstraints responses: '200': description: the ServiceInfoElement for Day Ahead Constraints. 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.dayaheadconstraints.info.html harvested: '2026-07-27' x-xml-element: ServiceInfo components: schemas: Constraint: type: object properties: BeginDate: type: string format: date-time ConstraintName: type: string ContingencyName: type: string InterfaceFlag: type: string enum: - Y - N - '-' MarginalValue: type: number required: - BeginDate - ConstraintName x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_Constraint 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 DayAheadConstraints: type: object properties: DayAheadConstraint: type: array items: $ref: '#/components/schemas/DayAheadConstraint' x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_DayAheadConstraints DayAheadConstraint: $ref: '#/components/schemas/Constraint' x-xsd-source: schemas/iso-new-england-web-services-ns0.xsd#type_DayAheadConstraint 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