I turn slow, underperforming websites and stores into tools that actually make money.
Full-stack developer based in Warsaw with 8 years of commercial experience. I specialise in custom WordPress and WooCommerce solutions - from PHP theme architecture and Gutenberg blocks in React/JSX to integrations with external ERP, PIM and API systems.
I work as a freelancer - directly with companies and through agencies. WordPress and WooCommerce are my core tools, but when a project needs more - a web app, mobile app or headless architecture - I have that covered too. Most projects are under NDA.
Uncommon Solutions
Solutions a typical agency won't build
A new website for a physiotherapy clinic - from content strategy to a custom WordPress theme. Instead of a generic brochure: a clear specialisation from the first screen, three offer paths and prices shown in the context of each service. Mobile PageSpeed went up from 75 to 94.
A React Native mobile app (iOS + Android) for storing sensitive data with two-key encryption - the data stays unreadable even if a backup is compromised. Backups go to the user's own cloud (iCloud / Google Drive), so no one else ever touches the files.
I turned multi-step email ordering into an interactive in-browser configurator - the client designs the product, sees the price and submits the order without waiting for a quote. The order lands straight in a panel with complete data, payment is linked to it automatically, and client communication happens in one place.
I rebuilt the store from scratch on a custom WooCommerce theme - no off-the-shelf template, no plugin bloat. The mobile PageSpeed score went from 75 to 100, pages load instantly, and the client manages content and products on their own.
Tailored WordPress and WooCommerce solutions built with performance, usability, and growth in mind.
Stores & E-commerce
I build new stores or rebuild existing ones. Custom code from scratch - no marketplace templates.
PageSpeed 90+ on mobile guaranteed, or the consultation fee is refunded. Guarantee conditions are verified in the audit before work starts.
WordPress & Front-End
When WordPress Isn't Enough
Web applications, SaaS platforms and projects where you need full control over architecture and performance.
Content in WordPress, frontend in Next.js. A familiar CMS for the client, a modern stack for the developer.
One codebase, two platforms. Battle-tested in production apps with encrypted storage and gamification.
Integrations & Automation
I replace manual order handling and repetitive processes with tools that run without human input.
What clients say about working with me
I run an online cosmetics store and I know that at this level of sales, the biggest cost is not the glitch itself but the time when nobody is dealing with it. That is why, when choosing someone to handle the technical side of my store, I looked above all at availability and communication.
Working with Marcin has been a good experience for exactly that reason. I can send a request by email or simply call if something is urgent, and every time I get a concrete answer: what will be done and when. If something more important comes up along the way, priorities can be rearranged without a week of explanations.
Deadlines are kept, and changes to the store are discussed in a language I understand, without hiding behind technical details. I recommend Marcin to anyone who runs an online store and is looking for someone they can rely on day to day, not only for a one-off project.
swiss-smile-beauty.plOur collaboration with Marcin began in uncomfortable circumstances. Our website had been infected with malware and we needed someone to get it under control. The site was cleaned up and secured, and along the way I learned where the problem had come from and what to do so it would not happen again. That is rare, because it usually ends with just removing the symptoms.
We have been working together on an ongoing basis ever since, for several years now. Marcin handles day-to-day changes to the website and implements new things we want to show our clients. I report what is needed and I am told when it will be ready. I do not have to follow up or keep an eye on it.
The biggest value for me is continuity. Marcin knows our website inside out, so we do not start every conversation by explaining how everything works on our side. I recommend him to anyone looking not for a one-off contractor, but for someone to work with for the long term.
poludnik21.plA custom WooCommerce store built without a ready-made template starts from €3,500. The price depends on the number of products, required integrations and the level of customisation. Typical delivery time is 3–8 weeks.
A PageSpeed audit and optimisation costs from €900 and usually takes 3–7 business days. It covers Core Web Vitals analysis, image and font optimisation, elimination of render-blocking scripts, cache and CDN configuration, removal of unnecessary plugins and database query optimisation. A score of 90+ on mobile is guaranteed - otherwise I refund the consultation fee. The guarantee applies to the site's score without third-party scripts added at the client's request (chat, marketing) and with hosting that meets minimum requirements - I verify both during the audit before work starts.
I start with a free discovery call (30–60 min) to understand the project's goal, scale and expectations. Then I prepare a quote with the scope of work and schedule. After acceptance, I work iteratively - regular contact, phased reviews, no surprises at the end. I use email or Slack for communication, reporting through Notion or a project document.
More and more users are searching for products and services through AI assistants (ChatGPT, Gemini, Perplexity). Websites with structured schema.org data, concrete facts and good information architecture are cited more often by AI models than sites without these elements. AI optimisation (GEO) is the natural evolution of classical SEO.
Want to start a project?
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You can also email me directly at: kontakt@ms-m.pl