# Hydro Ottawa Green Button Connect My Data (CMD) API

**Canonical:** https://apis.io/apis/hydro-ottawa/hydro-ottawa-green-button-connect-my-data-api/  
**Provider:** Hydro Ottawa — https://apis.io/providers/hydro-ottawa/  
**Documentation:** https://hydroottawa.com/en/residential/rates-billing/track-your-usage/green-button

Hydro Ottawa Green Button Connect My Data (CMD) API is published by [Hydro Ottawa](https://apis.io/providers/hydro-ottawa/) on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification. Tagged areas include Green Button, Connect My Data, ESPI, Energy Usage, and Smart Metering. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, and authentication docs.

Hydro Ottawa's mandated Green Button Connect My Data surface — the OAuth-authorized, machine-to-machine channel through which a customer can grant a third-party application ongoing access to their smart meter interval consumption and billing data in NAESB REQ.21 ESPI XML. It exists because Ontario Regulation 633/21 (Energy Data) under the Electricity Act, 1998 requires every covered Ontario electricity and gas distributor to implement Green Button CMD and DMD to ESPI v3.3 and certify with the Green Button Alliance. Hydro Ottawa's own Green Button page states the service is free, that the customer selects the data types, duration and frequency and may revoke at any time, that personally identifiable information is transmitted separately from usage data, and that the authorization flow must be initiated from the third-party application, which then redirects the customer into Hydro Ottawa's Green Button authentication. The customer-facing half of that flow is live and was confirmed at HTTP 200 on 2026-07-27 at https://hydroottawa.savagedata.com/Connect/Authorize, served by Savage Data Systems on Microsoft-IIS. No base URL is recorded here because Hydro Ottawa publishes no ESPI base URI, no API reference, no OpenID Connect discovery document and no first-party specification — a developer receives connection details only after completing onboarding. To integrate you must complete Hydro Ottawa's third-party onboarding at https://ottawaonboarding.savagedata.com/ and test and certify your solution with the Green Button Alliance. Conformance could not be independently verified from outside; see review.yml.

## Machine-readable artifacts (10)

- **OpenAPI** — https://raw.githubusercontent.com/api-evangelist/hydro-ottawa/refs/heads/main/openapi/hydro-ottawa-green-button-espi-openapi.yml
- **Overlay** — https://raw.githubusercontent.com/api-evangelist/hydro-ottawa/refs/heads/main/overlays/hydro-ottawa-green-button-espi-overlay.yaml
- **Documentation** — https://hydroottawa.com/en/residential/rates-billing/track-your-usage/green-button
- **Documentation** — https://hydroottawa.com/en/accounts-services/services/green-button/green-button-and-third-party-registration
- **Registration** — https://ottawaonboarding.savagedata.com/
- **Authentication** — https://hydroottawa.savagedata.com/Connect/Authorize
- **Certification** — https://www.greenbuttonalliance.org/testing
- **Documentation** — https://www.canlii.org/en/on/laws/regu/o-reg-633-21/latest/o-reg-633-21.html
- **Documentation** — https://www.oeb.ca/sites/default/files/OEB-Staff-Guidance-for-Implementation-of-Green-Button-20211101.pdf
- **APIsJSON** — https://raw.githubusercontent.com/api-evangelist/hydro-ottawa/refs/heads/main/apis.yml

## Tags

Green Button, Connect My Data, ESPI, Energy Usage, Smart Metering, Consumer Data, Ontario, Canada

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/hydro-ottawa/hydro-ottawa-green-button-connect-my-data-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/hydro-ottawa/.