Purchase the Standard

Purchase the ESPI Standard

The Green Button® Certification tests require the applicant to comply with the North American Energy Standards Board (NAESB) copyright policy.  This requires that all implementers of the NAESB REQ.21 Energy Services Provider Interface (ESPI) standard (commonly called Green Button®) undergoing testing must have purchased NAESB REQ.21 ESPI ver 4.0, NAESB REQ.21 ESPI ver 3.3, or have received either version as a benefit of NAESB membership.

To determine if a Certification Candidate has purchased the standard, the Test Administrator will access the NAESB Purchased Standards (PDF) document and search for the Candidate’s company name.


Version 4.0

Version 4.0 is the latest version of the standard.

In December of 2023, NAESB released the version 4.0 ESPI standard.  It includes the changes found in version 3.3 and additionally:

  • Updated security requirements to TLS 1.3 as a minimum
  • Added support to allow Bill Images (PDF and/or other formats) to be requested and received by a platform that supports the option using the Connect My Data (CMD) method.


Version 3.3

Version 3.3 is still currently available for purchase.

In 2019, NAESB ratified enhancements to the standard, which was published in 2020, and included the following changes:

  • Replaced OAuth 1.0 with OAuth 2.0 for Confidential Clients
  • Updated security requirements to TLS 1.2 as a minimum
  • Revised the Energy Usage Information (EUI) data structure and definitions
  • Created the Retail Customer (PII) data structure and definitions
  • Deprecated original Use Cases that do not meet OAuth 2.0 data security requirements
  • Added Use Case for Download My Data (DMD)
  • Simplified Use Case 2: Customer Authorization process
  • Documented Standard ESPI Application Program Interface (API) formats


Order a copy of the standard here (PDF):