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KJ Logo
Available for senior contract roles

Crafting robust systems,
building elegant products.

I'm Krzysztof Janiec, a Senior Software Engineer specializing in backend architecture, performant full-stack development, and developer-first design systems.

@kj/design • Activated
BACKEND ARCHITECTUREROBUST

Distributed & Event-Driven Systems

Designed enterprise microservices at REWE Digital, Cinkciarz.pl, and Biot. Expert in transactional event streams (Kafka, RabbitMQ) and high-scale Java/Spring Boot & TypeScript/Node.js backends.

Kafka Cluster: Healthy
JVM / TS: Scaled
RICH FRONTEND & WEBGLACTIVE

Performant UIs & Interactive Graphics

Created a custom 3D WebGL voxel engine in Babylon.js with chunk streaming (60 FPS), real-time collaborative workspace synchronization via WebSockets, and heavy analytical React & Angular UIs.

WebGL Render: 60 FPS
WebSockets: Synchronized

Experience

12+ yrs

Backend

Java & Node

Frontend

React & Angular

JavaSpringTSNext.jsReactAngularNode.jsPostgreSQLDockerKubernetes

Services

What I Do & Deliver

I partner with teams to design, build, and optimize high-performance software systems. Here are the core services I provide.

Portfolio

Featured Work

View all workArrow right
next-jsTypeScriptTailwind CSSMDX

Personal Website

My personal website and portfolio built with Next.js 15, TypeScript, and Tailwind CSS v4. Features a modern glassmorphic design, dark mode support, blog with MDX, and optimized performance with excellent Lighthouse scores. Showcases my work, skills, and thoughts on software development.

ReactWebSocketReal-timeAgile

Planning Poker

Real-time collaborative estimation tool for agile teams. Enables remote teams to conduct planning poker sessions with instant vote synchronization, room management, and intuitive card selection. Built with modern web technologies for seamless team collaboration during sprint planning.

ReactTypeScriptMaterial UIVite

MUI Greyscale Admin Dashboard

A comprehensive, production-ready admin dashboard template with a minimalist greyscale design. Covers 27 feature domains including CRM, finance, inventory, marketing, and security — all built with React 19, Material UI v9, and Vite 7. Fully open source and ready to use as a starting point for your next internal tool or admin panel.

Babylon.jsWebGLTypeScriptResume

Cyberpunk Voxel City - Interactive Resume

An interactive 3D resume disguised as a browser-based game. Explore a sprawling cyberpunk city rendered entirely from voxels, discovering skill boxes that represent technical expertise. Features custom voxel engine with greedy meshing, procedural city generation, dynamic lighting effects, and chunk-based streaming for smooth 60 FPS performance. Think Minecraft meets Blade Runner in your browser.

Get in touch

Let's Build Something Extraordinary

Whether you're looking for a senior software consultant, backend architecture design, or a full-stack engineer to scale your SaaS product, I'm ready to collaborate.