# Hydro One

**Canonical:** https://apis.io/providers/hydro-one/  
**Website:** https://www.hydroone.com/  
**APIs profiled:** 1

Hydro One Limited (TSX: H) is Canada's largest electricity transmission and distribution service provider, transmitting and distributing electricity across Ontario — the province the company describes as "home to 38 per cent of Canada's population." It sits in the regulated wires tier of the value chain: it owns and operates the provincial transmission grid and a rural/regional distribution network serving roughly 1.5 million customers, while the Ontario market itself is operated by the IESO and rates are set by the Ontario Energy Board. Its API posture is defined entirely by regulation, not by product. Ontario Regulation 633/21 (Energy Data, under the Electricity Act, 1998) compels Ontario electricity and natural gas distributors to implement Green Button Download My Data (DMD) and Connect My Data (CMD) and to have those implementations certified by the Green Button Alliance. Hydro One publishes DMD as an authenticated XML export inside My Account, runs a live Green Button CMD OAuth 2.0 authorization surface at www.hydroone.com/green-button-cmd-home, and operates a published third-party vendor onboarding form and terms and conditions — but the CMD resource base URI, client credentials, and test accounts are issued privately during onboarding and are not published anywhere. There is no developer subdomain, no OpenAPI or Swagger definition, and no self-serve signup. The split is the finding: consumer energy data is available through a real, standards-based, mandated API that a developer can only reach by application and 90-day connectivity testing, while open grid and market data is entirely absent — Hydro One publishes no open data portal and no documented public system or outage API, leaving Ontario market data to the IESO.

## Kin Score — 29.8 / 100 (thin)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 29.8).

| Facet | Score |
|---|---|
| Discoverability | 66.7 |
| Contract Quality | 0.0 |
| Governance | 18.2 |
| Contract Governance | 18.2 |
| Operational Transparency | 0.0 |
| Developer Ergonomics | 45.2 |
| Commercial Clarity | 34.2 |
| Access Clarity | 34.2 |

Regulatory layer — **Energy & Utilities**: 53.4 (matched via tags).

## Agent readiness — 8.5 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | no |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Free · Application and approval required — onboarding: unknown, pricing: free, trial: no (confidence: high).

## APIs (1)

- **Hydro One Green Button Connect My Data (CMD)** — Hydro One's Green Button Connect My Data implementation, mandated by Ontario Regulation 633/21. A registered third-party vendor obtains an OAuth 2.0 authorization code after the...

## Security (2)

- **Hydro One Authentication** — oauth2/mutualTLS · 2 schemes
- **Hydro One Domain Security** — TLSv1.3 · HSTS · DMARC

## Tags

Energy, Canada, Utilities, Electricity, Grid, Smart Metering, Green Button, Energy Data, Transmission, Distribution

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/hydro-one/). Scores are computed from the provider's own public artifacts under a published rubric.