Modernizing a Large Enterprise Web Application

A web application that had grown over many years was being developed by several teams. Inconsistent patterns, missing type safety and low test coverage made changes increasingly slow and risky.

Feature development and modernization had to run in parallel — a development freeze was not an option.

Several teams worked in the same codebase, causing dependencies and conflicts.

Inconsistent state management made debugging and onboarding difficult.

• Incremental adoption of TypeScript, starting with shared modules and interfaces.
• Modularizing the codebase in a monorepo with clear boundaries between business domains.
• Consolidating state management with Redux Toolkit and RTK Query, and Zustand for local state.
• A testing strategy with component, integration and end-to-end tests, plus visual testing with Chromatic.
• A level-headed evaluation of microfrontends for independently deployable areas.

• Architecture concept and migration path
• Implementation of key migration steps and reference implementations
• Definition of coding standards and review guidelines
• Knowledge transfer and pairing with the teams involved

• A clearly structured codebase in which teams can work more independently
• More confidence in releases thanks to automated tests in the CI pipeline
• Easier onboarding of new developers through consistent patterns and type safety