Proposal for Limiting Queries in EES API Calls (Single Query per API Call)
Summary
This issue has been raised proposing to establish a limit on the number of queries permitted within a single Application Programming Interface (API) call. As there is potential for performance degradation and system instability that can occur when a large number of queries are made in a single API call to the Electricity Enquiry Services (EES) API. The aim would be to prevent overwhelming the system and ensure consistent response times and reliability. Therefore, this proposes implementing a limit of 1000 queries per single API call.
Latest update and next planned activity
Date of latest update
Latest Update
This Change Proposal has been implemented as part of the February 2026 REC Release.
Impacts Overview
Impacted Consumers
Electricity
Impacted REC Parties and Market Participants
Energy Supplier
Other
Impacted REC Services
Electricity Enquiry Service (EES)
Priority and rationale
Standard
Priority last updated on 29 May 2026
Change Reports, Impact Assessments, Consultations and Documents
Change Reports
Solution development
Problem Statement
The absence of a limit on the number of queries (batch processing) within a single API call could cause performance issues and system instability. As a result, system responsiveness may degrade when a large number of queries are made in a single call, impacting user experience and hindering the ability of the EES API to consistently meet user demands.
No documents available.
Change Plan
Request for Information
Completed
Start:
03 Jun 2024Due:
05 Jul 2024Completion:
05 Jul 2024Change Issue Group
Completed
Start:
05 Jul 2024Due:
01 Aug 2024Completion:
01 Aug 2024Original submission
Change details
Andres Alvarez - RECCo
3 Jun 2024
Change details
Proposal for Limiting Queries in EES API Calls (Single API Call With Multiple Queries)
RECCo is proposing the establishment of a limit on the number of queries permitted within a single API call. There could be a potential performance degradation and system instability that can occur when a large number of queries are made in a single API call to Electricity Enquiry Services (EES) API. By setting a maximum limit on the number of queries allowed per API call, the aim is to prevent overwhelming the system and ensure consistent response times and reliability.
APIs are designed to be used often for small amounts of data, rather than infrequently for large volumes of data. APIs are typically used with synchronously within a business process, rather than asynchronously.
Therefore, RECCo proposes implementing a limit of 1000 queries per single API call. This adjustment is intended to enhance both Enquiry Service's capacity to consistently meet user demands without impacting its operations. Additionally, the introduction of this limit would necessitate revisions to Section 3 (Service Functionality) and Section 5 (User Limits) of the Electricity Enquiry Service (EES) Service Definition, and relevant sections of the EES API Interface Specification and their relevant versions upon this change being discussed.
APIs are designed to be used often for small amounts of data, rather than infrequently for large volumes of data. APIs are typically used with synchronously within a business process, rather than asynchronously.
Therefore, RECCo proposes implementing a limit of 1000 queries per single API call. This adjustment is intended to enhance both Enquiry Service's capacity to consistently meet user demands without impacting its operations. Additionally, the introduction of this limit would necessitate revisions to Section 3 (Service Functionality) and Section 5 (User Limits) of the Electricity Enquiry Service (EES) Service Definition, and relevant sections of the EES API Interface Specification and their relevant versions upon this change being discussed.
The absence of a limit on the number of queries (batch processing) within a single API call could potentially cause performance issues and system instability. As a result, system responsiveness may degrade when a large number of queries are made in a single call, impacting user experience and hindering the ability of the EES API to consistently meet user demands. By implementing a limit of 1000 queries per API call, the aim is to mitigate these issues and ensure more reliable service performance.
Upon implementation of the hard limit, the following processes would be implemented in addition to any relevant development work our Service Provider is to complete:
• The EES API would return a specific error message indicating that the user have exceeded the rate limit.
• Exceeding the rate limit could cause slower response times for your queries.
Upon implementation of the hard limit, the following processes would be implemented in addition to any relevant development work our Service Provider is to complete:
• The EES API would return a specific error message indicating that the user have exceeded the rate limit.
• Exceeding the rate limit could cause slower response times for your queries.
• RECCo seeks agreement from industry upon the proposed limit for the number of queries allowed within a single API call (batch processing).
• Relevant REC documentation would need to be updated.
• RECCo will ensure that the change is communicated effectively to all relevant parties.
• We will continue utilising our existing mechanisms for monitoring API usage and performance. Evaluate the impact on system stability, responsiveness, and user satisfaction to ensure that the solution effectively addresses the identified issues.
• Relevant REC documentation would need to be updated.
• RECCo will ensure that the change is communicated effectively to all relevant parties.
• We will continue utilising our existing mechanisms for monitoring API usage and performance. Evaluate the impact on system stability, responsiveness, and user satisfaction to ensure that the solution effectively addresses the identified issues.
RECCo is able to share data on past API usage patterns, performance metrics, and any instances of system instability or degradation associated with high query volumes can help contextualize the need for the proposed change.
Impacts
Electricity
Other (please provide details in Additional information box below)
We anticipate this change to be of low impact to EES Users.
The proposed change would primarily impact EES users API Users in scenarios where the number of queries per single API call surpasses 1000. Whilst such occurrences are infrequent in current practice, we acknowledge that the dynamic nature of the energy market landscape may introduce changes in the future. Therefore, implementing this limit serves as a proactive measure to ensure system resilience and performance.
The proposed change would primarily impact EES users API Users in scenarios where the number of queries per single API call surpasses 1000. Whilst such occurrences are infrequent in current practice, we acknowledge that the dynamic nature of the energy market landscape may introduce changes in the future. Therefore, implementing this limit serves as a proactive measure to ensure system resilience and performance.
No details provided
The introduction of this limit would necessitate revisions to Section 3 (Service Functionality) and Section 5 (User Limits) of the Electricity Enquiry Service (EES) Service Definition, and relevant sections of the EES API Interface Specification and their relevant versions upon this change being discussed.
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Energy Suppliers
We anticipate that this impact will be of low impact to a small number of Suppliers and TPIs.
No details provided
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No
No details provided
Priority & timing
No
N/A
Ideally, for the required amends to be made to the EES API
MHHS Code Freeze - would need alignment with C&C Group
No details provided
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Activity
Comments Deadline for Change report - Final Change Report has been updated to 18 Nov 2025
Status has been changed to Implemented.
Implementation Date has been updated to 27 Feb 2026.
holly.law has been allocated as Lead Analyst.
Change report - Final Change Report has been updated to Comments deadline for R0179 - Change Report - Final Recomendation.pdf - 2025-08-16.
holly.law has been allocated as Lead Analyst.
maxime.van-eyseren has been allocated as SME.