Hi, my name is
Štěpán Kameník
Freelance Java Developer
I help companies turn ideas into working software – mainly with Java/Spring Boot on the backend and Next.js on the front. After 7+ years in enterprise development (and a few side projects of my own), I care most about clear architecture, good DX, and happy users.
01. About Me
I'm a freelance Java & Next.js developer helping startups and teams ship real products – from internal tools to full SaaS platforms. With 7+ years of experience, I focus on backend-heavy systems that stay fast, stable, and maintainable as they grow.
Most of my work is in Java / Spring Boot, REST APIs, microservices and cloud-native setups. Recently I've been building more AI-powered features – mainly RAG systems over private data, internal assistants for complex domains, and small copilots that automate reporting and routine workflows.
I also work with Kotlin Multiplatform (KMP) to share business logic across iOS and Android apps, and with Next.js to build modern dashboards and UIs. I care a lot about clean architecture, good developer experience, and observability, so shipping new features stays as smooth as possible.
Clean Code
Writing readable, tested Java & TypeScript that future me won’t hate.
Microservices & APIs
Spring Boot microservices, RESTful APIs, and event-driven systems.
Cloud Native
Docker, Kubernetes, CI/CD pipelines, and cloud-native workflows.
AI & Automation
RAG systems, OpenAI integration, and internal copilots for real-world apps.
02. Skills & Technologies
languages
backend frameworks
FRONTEND & UI
DATABASES & STORAGE
DEVOPS & CLOUD
TESTING & QUALITY
AI & AUTOMATION
tools
MOBILE / KMP
03. Client Work
Freelance Application developer
FG Forrest a.s.Design and maintain backend services for some of the largest e-commerce platforms in Czechia, integrating with ERP and logistics systems and ensuring reliable, high-availability operation.
Industrial and experimental researcher - prototype evitaDB
University of Hradec KrálovéResearched and developed an e-commerce database prototype (evitaDB) on top of Elasticsearch, designing data models and search APIs and running performance experiments.
Backend Developer
Unicorn a.s.
Developed backend modules for an electricity market platform, implementing trade and settlement logic in Java/Spring and supporting reliable daily market operations.
04. Featured Projects
Featured Project
TimeIn.one – Time Tracking & Planning Platform
A SaaS tool for freelancers and small teams that combines time tracking, weekly planning, and analytics. Includes calendar-style scheduling, AI-powered summaries, and integrations with external tools. Designed and implemented the core backend, APIs, and modern dashboard UI.
Featured Project
EvitaDB NoSQL competitor implementation
A high-performance e-commerce database engine prototype built on top of Elasticsearch. Focused on fast product search, flexible filters, and complex pricing/catalog scenarios. Worked on data modelling, query pipelines, and performance experiments for real-world e-shop workloads.
Other Noteworthy Projects
Upnio.app
Currently proof-of-concept, a mobile app for iOS and Android that learns users basic world knowledge and provides personalized recommendations based on their interests and habits using AI. Built with Kotlin Multiplatform, integrating with the Upnio API in Java.
Babylon
Localization automation tool (“Babylon”) that syncs translation files with Google Sheets. It exports messages for translators, re-imports completed translations to update resource files, writes JSON snapshots of translation state, and can run both as a Maven plugin and as a standalone console app.
Personal Brand Website for a Spiritual Guide
A personal portfolio website built with Next.js and Tailwind CSS.
05. What's Next?
Get In Touch
I'm currently booking new freelance engagements. If you need help shipping backend features or rescuing service reliability, let's talk about how I can support your team.