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milan.webdeveloper@gmail.com

Challenges

The companys flagship application was a monolithic AngularJS project, aging, fragile, and struggling to keep up with growing user expectations. The CEO expressed ongoing frustration: “Every deployment breaks something.” Users, too, weren’t shy in their feedback. The app was slow, unresponsive, plagued by layout shifts, and prone to crashes. Complicating matters, the company wasn’t reliant on a single app, it had three active projects, each with their own quirks and dependencies. Any migration needed to be done carefully, without risking business continuity or disrupting the user experience.

Strategy

Our approach began with a bold but pragmatic plan, embed new React and TypeScript modules directly into the existing AngularJS application. This hybrid solution, developed in close alignment with the CEO and CTO, allowed us to roll out improvements incrementally while still supporting legacy functionality. We decided to use Material UI as our design system to establish visual consistency, accelerate UI development, and reduce design-debt across old and new modules. To support this cross-project transformation, we implemented a monorepo architecture, enabling better code sharing, developer consistency, and streamlined dependency management across all three projects.

Execution

The migration unfolded over two years, during which we:

  • Converted 17 key modules from AngularJS to React with TypeScript.
  • Introduced CI/CD pipelines, which drastically reduced deployment related regressions.
  • Standardized the UI with Material UI, giving the application a modern, cohesive look while speeding up front-end development.
  • Implemented Storybook for our component library which served as a single source of truth for development, design, and QA.
  • Maintained dual ecosystems, ensuring AngularJS and React could coexist safely during the transition.
  • Implemented TanStack Query to abstract away repetitive state and network management concerns, allowing developers to focus on feature logic instead of boilerplate.
  • Developed internal tooling and patterns to standardize module integration and testing across frameworks and projects.

Impact

The results spoke for themselves:

  • User engagement nearly tripled - average session duration rose from ~25 minutes to nearly an hour.
  • Post-deployment issues dropped by 99%, thanks to robust CI pipelines and automated testing which improved user trust and engineering velocity.
  • Customer feedback was overwhelmingly positive, with users praising the speed, responsiveness, and modernized interface.
  • Engineering teams are now fully working in React and TypeScript, with legacy code isolated and sunset plans in place.

What started as a brittle, high-risk application is now a responsive, maintainable React-based platform, delivered with minimal disruption and maximum value.