Green Button (NAESB REQ.21 ESPI)
Green Button is the North American standard for giving an energy customer machine-readable access to their own usage and billing data. The technical specification is NAESB REQ.21, the Energy Services Provider Interface (ESPI), which defines an Atom/XML data model and an OAuth 2.0 authorization flow. It ships in two very different forms — Download My Data, a file the customer exports, and Connect My Data, an actual API a third party can call with the customer’s consent.
Also known as ESPI, NAESB REQ.21, Energy Services Provider Interface, Download My Data, Connect My Data, DMD, CMD.
Providers that carry Green Button 23
These providers' own APIs.json profiles carry Green Button as a tag — the provider's statement that the standard is part of what it does. APIs.io has not verified the implementation on this page; the de facto profiles on this site are where that measurement exists. Ordered by Kin Score.
Read from the API Evangelist standards directory, facts verified 2026-08-17. Provider links come from the catalog's own identity tags and are rebuilt nightly. If this page is wrong about a standard or a provider, say so.