STORES & MARKETPLACES

Built on Medusa.js. Full control, zero SaaS platform limitations.

AI AUTOMATION

AI integrations that save time and increase profits.

Fullstack Medusa.js developer building online stores and multi-vendor marketplaces, plus websites and AI apps in Next.js

Not every technology makes sense. I only build systems that actually work. Modern websites, online stores and AI tools that help businesses sell and grow.

Your business. Your rules. Your system.

START TO GROW

WEBSITES THAT SELL

Fast, optimized, and built for conversion.

CUSTOM-TAILORED SYSTEMS

Exactly what your business needs.

Medusa.js

Next.js

React

TypeScript

Stripe

Node.js

PostgreSQL

Tailwind CSS

Framer Motion

Three.js

Docker

AWS

Railway

AWS S3

Resend

Netlify

Vercel

Sanity

GraphQL

Prisma

Git

Figma

Medusa.js

Next.js

React

TypeScript

Stripe

Node.js

PostgreSQL

Tailwind CSS

Framer Motion

Three.js

Docker

AWS

Railway

AWS S3

Resend

Netlify

Vercel

Sanity

GraphQL

Prisma

Git

Figma

Medusa.js

Next.js

React

TypeScript

Stripe

Node.js

PostgreSQL

Tailwind CSS

Framer Motion

Three.js

Docker

AWS

Railway

AWS S3

Resend

Netlify

Vercel

Sanity

GraphQL

Prisma

Git

Figma

Medusa.js

Next.js

React

TypeScript

Stripe

Node.js

PostgreSQL

Tailwind CSS

Framer Motion

Three.js

Docker

AWS

Railway

AWS S3

Resend

Netlify

Vercel

Sanity

GraphQL

Prisma

Git

Figma

[ 01 - About ]

Portrait of Arkadiusz Wawrzyniak, fullstack developer

Solutions that grow your business

I help businesses succeed online. Whether you need an online store or a marketplace on Medusa.js, a landing page that converts visitors into customers, or AI-powered apps to automate your workflows - I deliver complete solutions from start to finish.

You get a partner who understands your business goals. I handle everything: design, development, content management systems you can update yourself, and ongoing support. No technical knowledge needed on your end.

Get to know me

80%

Less manual work

100%

Headless

Templates

[ 02 - Services ]

What I can build for you

My specialisation is Medusa.js: online stores, multi-vendor marketplaces and commerce integrations written around your business model. How a Medusa.js project works

Medusa.js online stores

Full control over your store - no commissions, no growth ceiling.

B2C and B2B online stores on Medusa.js: open-source commerce, flexible checkout, product logic and integrations without the limits of closed SaaS platforms.

See details

Medusa.js multi-vendor marketplaces

A platform for many sellers, built around your business model.

Marketplace platforms on Medusa.js with vendor accounts, commission logic, custom payments and operational flows designed for scalable multi-vendor commerce.

See details

Websites

A site that brings in clients - not just looks good.

Modern business websites and landing pages on Next.js: lightning-fast load times, solid SEO and high conversion - ready for traffic from day one.

See details

Shopify stores & custom storefronts

Launch quickly today - without limiting tomorrow's growth.

Shopify stores for every stage of growth: from focused theme-based launches to custom headless storefronts built with Next.js or TanStack, tailored integrations and conversion-focused UX.

See details

AI integrations & automation

Less repetitive work, more time for what actually matters.

AI chatbots, RAG assistants, process automations and integrations with business data - solutions that genuinely lighten the load and speed up customer handling.

See details

Custom web applications

A system built around your business, not the other way around.

Web apps, B2B dashboards, MVPs and SaaS platforms built around real business logic - with clean architecture and room to scale.

See details

Consult Your Project

[ 02 - Work ]

Selected Projects

Artovnia E-Commerce - Medusa.js

Medusa.js e-commerce marketplace - 2025

Full-stack multi-vendor e-commerce marketplace built with Next.js and Medusa.js. Features advanced product management, rich features, secure Stripe payment processing, and a seamless checkout experience optimized for conversions.

View

3DPCC – ERP for 3D Print Farms

B2B SaaS / ERP - 2026

As Sole Architect & Lead Developer, I rebuilt a browser-only calculator MVP into a production-ready B2B SaaS ERP. The system features a modular monolith (Node.js 24, TypeScript, Drizzle ORM, Supabase), order state machine, stock reservation lifecycle with SHA-256 idempotency, tenant isolation with RLS, and an append-only audit log.

View

Glow & Serenity Spa Website

Business page - 2026

High-converting spa website with client-friendly content management system. Owners can update services, prices, and promotions themselves without technical help. Increased bookings by 40% in first month.

View

HWA / 火 - Korean BBQ

Web design - 2026

A conceptual frontend project simulating a luxury Korean BBQ restaurant. Built with Next.js featuring cinematic GSAP ScrollTrigger animations, a custom CSS architecture, and full i18n support.

View

Graphic Designer Portfolio

Portfolio website with CMS - 2026

An interactive portfolio and digital CV for a graphic designer. Custom animations, floating signature faces, and a fully CMS-editable layout - built to put the artwork first.

View

Interior Lighting Design Demo

Web design - 2026

Professional demo website for an interior lighting design company. Built around light, motion, and code. Real-time 3D rendering, GSAP, Canvas - no compromises on performance.

View

Alfa Romeo Demo

3d game demo - 2026

Interactive Three.js car experience with custom-built physics, sound system, dynamic lighting, and cinematic presentation.

View

Want to work together?

[ 04 - Solutions ]

How can I help?

Landing Pages & Business Websites

Getting traffic, but not enough inquiries?

Conversion- and SEO-focused landing pages on Next.js - fast loading, responsive, modern design, high conversion rates and excellent scalability.

Medusa.js & Shopify Online Stores

Your platform starting to hold you back?

Medusa.js when your sales logic needs full control and code you own, or Shopify, from a fast theme-based launch to a custom headless storefront on Next.js.

Marketplaces & Multi-Vendor Platforms

Looking to build a platform for multiple sellers?

Medusa.js marketplaces with custom commission logic, split payments and vendor account management, tailored to your business model from the first line of code.

Custom Web Applications

No off-the-shelf tool fits your workflow?

Web applications and internal systems on Next.js - built around real business logic, with architecture that grows alongside your company.

SEO-Optimised Websites

Competitors ranking higher, despite your offer being better?

Next.js sites with technical SEO built in from the ground up: fast loading, proper semantics, Core Web Vitals and structure that both users and Google understand.

Let's talk about your project

[ 05 - Blog ]

Latest from the blog

Fresh notes on Medusa.js, e-commerce, AI and the decisions behind modern digital products.

Sep 29, 2026

Migrating 3DPCC to production: 7 hours of downtime and what filled them

Rebuilding 3DPCC from a cost calculator into a production management system took a seven hour planned outage. Five of those hours went to data migration scripts and verifying their results, not to shipping code. Here is the plan, the window, and what I took from it.

Aug 30, 2026

Marketplace Compliant with Regulations Without Building Amazon

How to translate GPSR, DSA, GDPR, BDO, and DAC7 obligations into a reasonable MVP, without designing infrastructure for millions of listings. A practical architectural overview for marketplace builders.

Aug 28, 2026

How to Extend an Existing Online Store with a Marketplace

A marketplace layer can be added to an existing online store without replacing the underlying platform. Inventory synchronization across vendors is the most complex part of the integration. The store operator retains full control over orders and the customer experience.

View all posts

[ 06 - Contact ]

Let's work together

Emailkontakt@appcrates.pl

Phone+48 733 433 230

LocationWrocław, Poland