We have launched our consultation on Phase 1a of the Tariff Interoperability Project, alongside publication of the latest Phase 1a API Technical Specification. The consultation is focused on identifying any remaining defects, inconsistencies or implementation blockers ahead of finalisation of the API Technical Specification, and the associated Retail Energy Code (REC) changes required to support its implementation.
Phase 1a represents the first implementation phase of the wider Tariff Interoperability Project. The consultation provides stakeholders with an opportunity to review the proposed arrangements and help identify implementation blockers or defects in the final approach ahead of implementation.
What are we consulting on?
The consultation sets out the proposed updates to the Phase 1a technical documents, including:
- the API Technical Specification
- Energy Market Data Specification (EMDS)
- the Standards Definition Document
As part of the consultation, RECCo is publishing an updated version of the Phase 1a API Technical Specification. Suppliers progressing their Phase 1a implementation should use this latest version as the basis for their ongoing build, rather than earlier versions of the specification: RECCo Developer Portal
The consultation is intended to identify any remaining material defects, inconsistencies or implementation blockers. Any further changes arising from consultation feedback will be clearly communicated.
We encourage all interested stakeholders to review the consultation materials and provide feedback on the proposals.
Technical Consultation Letter & Annex A (Questions)
Annex B (TI API Technical Specification)
Annex C (Energy Market Data Specification)
Annex D (Standards Definition Document)
Tariff Interoperability Bespoke Non Domestic Contracts – Explanatory Note for Stakeholders
Consultation Response Proforma
Have your say
The consultation will be open for three weeks until 17 September 2026
Responses should be submitted using the consultation response proforma and returned to tariffinteroperability@retailenergycode.co.uk by the consultation closing date.
What happens next?
Once the consultation closes, RECCo will review all responses before publishing the outcome.
Stakeholder feedback will help identify any material defects, inconsistencies or implementation blockers before the technical documents are finalised.
We encourage stakeholders to review the proposal and respond to the consultation to help identify defects, inconsistencies, or implementation blockers before the next stage of delivery.
For any questions about the consultation, please contact tariffinteroperability@retailenergycode.co.uk.
