Market User Interface

The MISO Market User Interface (MUI) allows Market Participants to transact with the MISO Energy & Ancillary Services Market. Designed over 15 years ago, the MUI requires modernization to meet future performance, usability, reliability and security needs. 

MISO is encouraging stakeholders to enagage in the two-year planning, testing and verification process to replace the MUI by April 2021. This change is part of the larger Market System Enhancement (MSE) program to modernize the MISO Energy & Ancillary Services Market system. 


Member Readiness

The MUI 2.0 Member Readiness Application is now available and allows MISO to gauge member engagement and readiness throughout each phase. Members are responsible for updating their readiness status through the two-year effort on a monthly and as needed basis. The application is only available in the MISO Customer Connectivity Enviroment (CCE) and is accessible to any member with a CCE certificate. 

Frequently Asked Questions


  • Other Market Portal navigation tiles
    • Asset Registration Tool
    • Settlements
    • Financial Transmission Rights
    • OATI OASIS and webTrans
  • Other APIs such as
    • Outage Scheduling

Module-E Capacity Tracking (MECT)

MISO will roll this plan out over the next two years. The 3-month parallel operations target is Jan-Mar 2021 with legacy MUI retirement in April 2021. Ahead of the parallel operations period, MISO will provide a test environment and validate Market Participant preparedness to ensure a smooth transition.

Below is the proposed timeline, divided into four phases.

Phase 1 – Customer Engagement (2019) – MISO host a series of workshops and roll out specifications. This is when you can provide feedback on design, begin your planning and prepare for development and testing.

Phase 2 – Development and Testing (2020) – Focus will shift to completing development and testing.

Phase 3 – Parallel Operations (Q1 2021) – MISO will have both the legacy and MUI 2.0 available in production. Market Participants can use either system and choose the best window to migrate over. Goal is to have 100% of Market Participants migrated to MUI 2.0 by end of March 2021.

Phase 4 – Legacy Retirement (April 2021) – MISO will shut down the legacy MUI and only the new MUI 2.0 will be available.

Designed over 15 years ago, the MUI requires modernization to meet future performance, usability, reliability, and security needs. 

The MUI allows Market Participants to submit market transactions and query market results. The current MUI is a Web Services/XML based design with a XSD scheme defining the transaction. The new MUI is a RESTful API/JSON design with an OpenAPI Specification (Swagger) schema

In addition to the technical changes, a few usage patterns will change. For example, the new MUI allows for one submittal per transaction instead of multiple submittals in a single transaction. 

Both the API and the user interface is changing. 

MISO will release preliminary and final technical specification as they become available. 

The transaction types, transaction content requirements and market rules will remain the same. 

MUI Timeline_4_8_19.png