RTE
RTE: graphic and technological redesign of the éCO2mix mobile application
RTE (Electricity Transmission Network) manages the public electricity transmission network in France. It ensures the continuous circulation of high-voltage electricity to distributors and major consumers, while maintaining the balance between consumption and production. RTE plays a key role in the energy transition by guaranteeing reliable and transparent access to sector data.
2025
Modernising éCO2mix: meeting accessibility and usability challenges for all users
The éCO2mix mobile application, developed in 2011 by SQLI for RTE, serves as a public showcase: it displays real-time data on electricity production and consumption in France, enabling users to monitor, visualise, and understand the electrical system of a country that is decarbonising, reindustrialising, and adapting to European and regional ambitions.
Designed with input from its first users, the éCO2mix app provides direct access to continuously updated data on the French electricity system. Free, intuitive, and available on iOS and Android, it is intended for anyone wishing to follow electricity trends closely, regardless of usage.
The back end of the application, managed by SQLI since 2023, also powers RTE’s institutional website.
RTE sought to modernise its mobile application and offer a smoother user experience.
This project addressed several strategic objectives:
- Technological and graphic redesign (UX/UI) of the mobile application
- Technical migration of a back-end component to a Java microservices architecture based on a hexagonal model
A comprehensive approach: UX/UI recommendations, advanced technical architecture, and digital accessibility
Mobile application redesign:
- UX/UI recommendations to modernise the design, improve the user experience, and align it with current mobile application standards
- Development in React Native, a cross-platform technology replacing the previous native Android and iOS applications
- Support in implementing best practices for digital accessibility
Technological redesign of the back end:
- Architectural revision with the addition of a Java microservices component within the existing back end to enhance modularity and scalability
- Performance and reliability testing, both functional and technical
- Compliance with API standards to ensure interoperability and security
Concrete results: traffic doubled and highly positive user feedback
The new éCO2mix application, live since June 2025, is more modern and higher performing. It was quickly embraced by users: daily traffic has doubled, and reviews on the app stores are overwhelmingly positive.
The support provided by SQLI stood out for its exceptional quality. Their technical expertise, attentive approach, the relevance of their recommendations, and their ability to propose solutions aligned with our challenges were decisive in the project’s success. They met the deadlines while maintaining a high level of internal satisfaction. The team established a genuine relationship of trust and supported us effectively at every stage.