Mateusz Zieliński
From: Poland
Location: Zelgoszcz, PL
On Useme since 25 September 2026
About me
Fullstack PHP Developer with 2+ years of commercial e-commerce experience. I maintain and develop an online store engine powering nearly 100 live shops, so I know carts, payments and shipping from the inside.
How I can help: - business websites and online stores, from design to launch - payment (PayU, Przelewy24) and courier (InPost, DPD, ORLEN Paczka) integrations - importing products, prices and stock from wholesalers (XML, CSV, API) - product configurators with dynamic pricing - fixing, extending and speeding up existing PHP sites, including legacy code - MySQL optimization and slow query tuning
Tech: PHP 8, Laravel, MySQL, JavaScript, Tailwind CSS. I also run my own CMS platform that I use to build client websites.
How I work: a clear quote and deadline before we start, regular progress updates along the way, and support after launch if anything needs adjusting.
Categories
CV / Résumé
Feb 2026 - Now
Fullstack Developer - Core Engine Maintainer
Welcon
Maintaining and developing the core of an e-commerce platform powering nearly 100 shops. Rebuilt the checkout from scratch, built a product configurator with dynamic pricing, integrated PayU, Przelewy24, InPost, DPD and ORLEN Paczka.
Jul 2024 - Jan 2026
Fullstack Developer
Webemo
Developing a custom e-commerce engine: new backend and frontend features for client needs, fixing production bugs, third-party API integrations and responsive store layouts. PHP, MySQL, JavaScript.
Portfolio
My own CMS platform for building business websites, with separate admin and client panels, role-based permissions and software licensing via REST API. Laravel, Livewire, Alpine.js, Tailwind CSS, MySQL.