Hydro One
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.
Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.
API Evangelist profiles Hydro One the way a machine reads it — 4 machine-readable artifacts across 1 API, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Hydro One scores 29.1/100 (thin), with a separate agent-readiness read of 3/100 (human only). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-08 · rubric v0.20.0
Put this on your own site. The badge is drawn live from Hydro One's current Kin Score — paste it once and it updates itself every time the score is recomputed. It follows your visitor's light or dark setting, and it links back here so anyone who sees it can read the full breakdown.
<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/hydro-one/"
title="Hydro One on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/hydro-one.svg"
alt="Hydro One Kin Score — API readiness rating by API Evangelist" width="150" height="150" loading="lazy">
</a>[](https://providers.apievangelist.com/providers/hydro-one/)<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/hydro-one/"
title="Hydro One on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/hydro-one/card.svg"
alt="Hydro One Kin Score — API readiness rating by API Evangelist" width="340" height="120" loading="lazy">
</a>More shapes, themes and sizes → · Score as JSON · How badges work
How we profile Hydro One
Each block below is one kind of artifact we hold for Hydro One. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 1
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
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 Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Scopes 1
OAuth scopes are the vocabulary of least-privilege access. Profiling them shows exactly what an integration — or an agent acting on a user's behalf — is allowed to do.
OAuth scopes governing access to this provider's APIs.
Resources
Every other property we hold for Hydro One — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 3
Portal, sign-up, and the first successful call
Documentation 1
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 3
Pagination, idempotency, versioning, errors, and events
Access & Security 3
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 3
Pricing, plans, and the legal terms of use
Company 4
The organization behind the API
Other 1
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/hydro-one · machine-readable index on apis.io
This is an independent, third-party profile of Hydro One, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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you will get a person, not a form — we will tell you exactly which public URLs this profile was built from.