# IESO — Independent Electricity System Operator (Ontario, Canada)

> The Crown corporation that operates Ontario's bulk electricity system and administers the province's wholesale electricity market. Its API posture splits cleanly in two: a genuinely open, anonymous market and system data repository at reports-public.ieso.ca serving 139 report directories as CSV, XML and XLSX, and a set of documented but strictly participant-gated REST and SOAP interfaces requiring IESO-issued machine accounts. There is no consumer energy data API — Ontario's Green Button mandate (O. Reg. 633/21) binds licensed distributors, not the system operator.

Generated by API Evangelist from https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/apis.yml on 2026-07-27. IESO does not publish an llms.txt of its own (https://www.ieso.ca/llms.txt returned 404).

## Start here — the open surface

- [Public Report Repository](https://reports-public.ieso.ca/public/): Anonymous HTTPS file repository. 139 report directories. No account, key, registration or licence acceptance. This is the only IESO interface a third party can use today.
- [Data Directory](https://www.ieso.ca/en/Power-Data/Data-Directory): The human catalogue of what is published, by category, with direct links.
- [Power Data](https://www.ieso.ca/en/Power-Data): Landing page for Ontario supply, demand and price data.
- [Outbound Automated Document API specification (IMO_SPEC_0100)](https://www.ieso.ca/-/media/Files/IESO/technical-interfaces/xml-automated-docs/IMO_SPEC_0100.pdf): The actual interface specification for the public repository — URL patterns, file naming, versioning, links, retention and recommended polling frequency.

### How to address a report

`https://reports-public.ieso.ca/public/<Document Identifier>/PUB_<Report>_<YYYYMMDD>_v<n>.<ext>`

Prefer the **Global Link** — the same filename with the date and version removed (for example `https://reports-public.ieso.ca/public/Demand/PUB_Demand.csv`) — which always resolves to the latest version of the most recent reporting period. A **Local Link** drops only the version and resolves to the latest version within one reporting period.

Recommended polling: 15–30 seconds for 5-minute reports, 4–10 minutes for hourly, 30–60 minutes for daily. Never infer hour-of-day from the `_v<n>` suffix — IESO states explicitly that version numbers mean nothing but sequence.

## Developer surface

- [Technical Interfaces](https://www.ieso.ca/sector-participants/technical-interfaces): The de facto developer portal. Index of every documented IESO interface with specs, WSDL, XSDs and sample payloads. No signup and no key issuance happen here.
- [IT Release Schedule](https://www.ieso.ca/sector-participants/change-management/it-release-schedule): The change log and the roadmap in one page. Category 3 releases require participants to change their own technical interfaces.
- [Pending Changes — Documents](https://www.ieso.ca/Sector-Participants/Change-Management/Pending-Changes-Documents): Per-baseline change package, open for comment.
- [Supported Client Platforms](https://www.ieso.ca/en/Sector-Participants/Supported-Client-Platforms)
- [Contact / Customer Relations](https://www.ieso.ca/Corporate-IESO/Contact): customer.relations@ieso.ca, 1.888.448.7777.

## APIs

- [IESO Public Reports Repository](https://www.ieso.ca/en/Power-Data/Data-Directory): `https://reports-public.ieso.ca/public/` — anonymous. Not a REST API: no query parameters, filtering, pagination or content negotiation. A documented, schema-backed retrieval interface.
- [IESO Reports Site REST API](https://www.ieso.ca/sector-participants/technical-interfaces): `https://reports.ieso.ca/api/v1.4` — Axway SecureTransport. HTTP Basic plus mandatory `?idp_id=ieso`. Confidential participant reports only; returns 401 anonymously. SFTP on port 22 is the alternate interface.
- [MIM Web Services](https://www.ieso.ca/sector-participants/technical-interfaces): `https://webservices.ieso.ca/emim` — SOAP, 23 operations covering real-time energy, operating reserve, schedule, bilateral, daily-dispatch and forebay bid upload/query/cancel plus market status, market messages and health check. UserID/password with IP allow-listing; unreachable from the open internet.
- [Registration System Facilities API](https://www.ieso.ca/sector-participants/technical-interfaces): `https://online.ieso.ca/suite/webapi/reg-v1-facilities` — Appian API key.
- [Retrofit System API](https://www.ieso.ca/sector-participants/technical-interfaces) and [Retrofit Service Provider API](https://www.ieso.ca/sector-participants/technical-interfaces): Save on Energy conservation programs, Appian API key. SPEC-188 is being replaced by SPEC467 at baseline 56.0 (2026-09-09).
- [Dispatch Service Web Service](https://www.ieso.ca/sector-participants/technical-interfaces) (SPEC-154) and [Dispatch Notification Service](https://www.ieso.ca/sector-participants/technical-interfaces) (SPEC-155): real-time dispatch, request/response and push.
- [OCSS Web Service](https://www.ieso.ca/sector-participants/technical-interfaces) (SPEC-113): outage request submission. The write side is gated; the resulting outage data is republished anonymously in the `TxOutages*` directories.

## Specs and schemas

- [MIM WSDL](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/wsdl/ieso-mim-web-services.wsdl): service `emim-web-service`, 23 operations, target namespace `http://webservices.ieso.ca/emim/`.
- [MIM XSD](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/xsd/ieso-mim-web-services.xsd): 62 complex types, 267 elements.
- [Document envelope XSD](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/xsd/ieso-document-r1.xsd) and [IMODocument envelope XSD](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/xsd/ieso-imo-document-r1.xsd): the two live generations of the automated-document envelope.
- Eleven report-specific XSDs under [xsd/](https://github.com/api-evangelist/ieso/tree/main/xsd) covering adequacy, commit, pre-dispatch energy and prices, reliability commit, financial binding status, dispatch advisory, unconstrained HOEP, generator output capability and intertie schedule/flow.

There is **no OpenAPI, Swagger, AsyncAPI, GraphQL, MCP server, Postman collection or JSON Schema** anywhere in the IESO estate. `/openapi.json`, `/swagger.json`, `/api-docs` and `/.well-known/` were probed on www.ieso.ca, reports-public.ieso.ca, reports.ieso.ca and online.ieso.ca on 2026-07-27 and all returned 404 or an HTML soft-200.

## API Evangelist artifacts

- [apis.yml](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/apis.yml)
- [Authentication profile](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/authentication/ieso-authentication.yml)
- [API conventions](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/conventions/ieso-conventions.yml)
- [Error codes](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/errors/ieso-error-codes.yml)
- [Data model](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/data-model/ieso-data-model.yml)
- [Lifecycle](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/lifecycle/ieso-lifecycle.yml)
- [Changelog](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/changelog/ieso-changelog.yml)
- [Sandbox](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/sandbox/ieso-sandbox.yml)
- [Conformance](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/conformance/ieso-conformance.yml)
- [Dispatch notification webhooks](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/asyncapi/ieso-dispatch-notification-webhooks.yml)
- [Packages](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/packages/ieso-packages.yml)
- [Well-known](https://raw.githubusercontent.com/api-evangelist/ieso/refs/heads/main/well-known/ieso-well-known.yml)
- [Agent skills](https://github.com/api-evangelist/ieso/tree/main/skills)

## Client libraries

IESO ships one first-party client: the [MIM Web Services Toolkit (MWT)](https://www.ieso.ca/-/media/Files/IESO/technical-interfaces/mp-submissions/MWT-User-Guide.pdf), a Java toolkit distributed as a ZIP from ieso.ca — not from any package registry. The community options for the public data are [gridstatus](https://github.com/gridstatus/gridstatus) (maintained, ships `gridstatus/ieso.py`) and [pyiso](https://github.com/WattTime/pyiso) (dormant since 2024).

## Optional

- [Terms of Use](https://www.ieso.ca/Terms-of-Use)
- [Privacy Policy](https://www.ieso.ca/privacy)
- [Blog](https://www.ieso.ca/en/Corporate-IESO/Blog)
- [Cyber Security Incident Reporting](https://www.ieso.ca/Sector-Participants/Cyber-Security/Cyber-Security-Incident-Reporting)
- [Connection Process](https://www.ieso.ca/Sector-Participants/Connection-Process/Overview) — how an organization becomes a market participant and thereby becomes eligible for credentials.