> Step-by-step modernisation of legacy systems while they keep running: characterisation tests, CI gates, strangler-fig pattern. Near Graz, Austria.
>
> Web page: https://balazscsorba.com/expertise/legacy-modernisation · Language: English · Also available in: [Deutsch](https://balazscsorba.com/de/expertise/legacy-modernisation.md) · [Magyar](https://balazscsorba.com/hu/expertise/legacy-modernisation.md)

Expertise

# Legacy modernisation – step by step, while the system keeps running

Your system stays online while it gets better. Tests pin down today’s behaviour, new parts grow next to the old ones, and every step is small enough to roll back.

Open for new projects

[Get in touch](https://balazscsorba.com/#contact) [See all references](https://balazscsorba.com/references)

## What I bring

-   ### Tests before changes

    Characterisation tests pin down what the system does today; CI gates and static analysis stop it from getting worse while it is rebuilt.

-   ### Module by module

    The strangler-fig way: new parts grow next to the old ones and traffic moves over one function at a time – no big-bang rewrite, no feature freeze.

-   ### Proven on real systems

    A TYPO3/PHP B2B shop refactored to 65% faster page loads (4.6 s → 1.6 s), a large SaaS app moved from Vue 2 to Vue 3, and a tightly coupled legacy system moved to a headless Vue.js setup.

## Projects that prove it

Real projects, real numbers – the full list is on the references page.

-   Messerle

    ### B2B shop refactor & speed-up

    Complete codebase refactor of a TYPO3/PHP B2B shop: 65% faster page loads (4.6 s → 1.6 s), a reliable order flow and stable Infor ERP and PIM integrations.

    -   TYPO3
    -   PHP
    -   Infor ERP
    -   PIM

    [messerle.at](https://www.messerle.at/)

-   INGENIOUS.BUILD

    ### Vue 2 → Vue 3 migration

    Led the migration of a large construction-management SaaS app to Vue 3, removing technical debt and making it ready for the long run.

    -   Vue 3
    -   TypeScript
    -   Vite

    via [INGENIOUS.BUILD](https://www.ingenious.build/)[ingenious.build](https://www.ingenious.build/)

-   Vioma

    ### Headless Vue.js architecture

    Moved a tightly coupled legacy system to a headless Vue.js setup and owned the Hungarian localisation of the UI.

    -   Vue.js
    -   Headless
    -   i18n

    via [Vioma](https://www.vioma.de/)[vioma.de](https://www.vioma.de/)

-   Zumtobel Group

    ### PIM migration to Pimcore

    500,000+ products, 14,000 categories and 50 product classes moved into Pimcore in 3 months, with a stable delta sync between SAP, PDB and Pimcore – ready for an on-time go-live in Italy.

    -   Pimcore
    -   PHP
    -   SAP
    -   Delta-sync

    [zumtobel.com](https://www.zumtobel.com/)

## Toolbox

-   Vue.js 2 & 3
-   Nuxt.js
-   React
-   Next.js
-   Svelte
-   TypeScript
-   PWA
-   SSG / SPA
-   Capacitor.js
-   Node.js
-   Express.js
-   PHP
-   REST APIs
-   Microservices
-   RabbitMQ

## Frequently asked questions

Do you refactor or rebuild?

Mostly I refactor. Where a part cannot be saved, I rebuild it and document why.

Does the system have to stop?

No. Changes go live in small, tested steps, and each one can be rolled back.

Which stacks?

PHP (TYPO3, Symfony, Spryker, Pimcore), TypeScript (Vue, Nuxt, React, Next.js, Node), Python and Go. With coding agents, a new stack is rarely a blocker.

Where are you based – and do you work remotely?

In Voitsberg, west of Graz in Styria, Austria. Remote across Europe and the UK, or hybrid in Styria.

Are you available?

Open for new projects. The quickest way to reach me is e-mail or LinkedIn.

Which languages do you work in?

English and Hungarian. Project communication, tickets, documentation and code are in English – I don’t work in German.

## Also on this site

-   [Code audit for AI-generated code](https://balazscsorba.com/expertise/code-audit)
-   [AI engineering & MCP servers](https://balazscsorba.com/expertise/ai-engineer)
-   [Vue.js & Nuxt development](https://balazscsorba.com/expertise/vue-nuxt-developer)
-   [B2B e-commerce & PIM](https://balazscsorba.com/expertise/b2b-ecommerce-developer)
-   [Game](https://balazscsorba.com/game)

## Sounds like what you need?

Tell me about your project or role – I’d love to hear from you.

[Get in touch](mailto:contact@balazscsorba.com) [Connect on LinkedIn](https://www.linkedin.com/in/balazs-csorba)