How E.ON Germany built OneApp: One customer experience across independent energy domains on AWS

This article describes how E.ON Germany built OneApp, a unified platform that brings commodity energy, solar, e-mobility, flexibility, and partner services into one customer experience using AWS services.

• Fragmented architecture prevented joint optimization of energy assets; OneApp consolidates five flexibility pools to reduce household energy costs substantially
• Shell architecture owns only identity, navigation, and design system; everything else deploys as independent micro-frontends using Webpack Module Federation
• Versioned composition manifest acts as control plane, enabling multiple live versions, canary deployments, and rollbacks without app store updates
• Trust broker exchanges central CIAM authentication into domain-specific credentials, supporting multiple identity models without migration
• AI features reuse the composition contract to assemble personalized screens from components across domains using Amazon Bedrock and OpenSearch
• Sensitive information filters and contextual grounding checks enforce safety for financial explanations

OneApp demonstrates how versioned contracts and decentralized ownership enable autonomous domain teams to ship independently while maintaining unified customer experience.