Ruslan Lomaka · A personal corner of the web

Curiosity usually turns into a project.

I’m Ruslan. I write code, learn German and run a Raspberry Pi homelab. Here are some things I’ve made along the way, the questions behind them and what I’m still figuring out.

Start with Java Sandbox Explore the language tools Say hello

Based in Husum, Germany. Built with curiosity; still a work in progress.

Further down the rabbit hole

One question leads to the next

Active experimental prototypePersonal project

Online Java Sandbox

What actually happens between clicking “Run” and seeing Java code execute on a server? I built this sandbox to find out. It’s an evolving prototype: a browser editor, a Java backend and disposable Docker containers, running on my Raspberry Pi.

Making room for other people

Building it alone was one kind of challenge. Making it understandable to someone else was another. I documented the architecture and added a simpler development mode so contributors could get started without recreating my home server.

A look under the hood

Java and Spring Boot backend
GitHub OAuth 2.0 authentication
PostgreSQL persistence
isolated Docker execution
automated tests and GitHub Actions
Checkstyle and SonarQube Cloud quality checks
self-hosting on a Raspberry Pi

Try live prototype View source and architecture

Online Java Sandbox development-mode editor interface — Development-mode interface built from the project’s current source.

From my German lessons

Learning German, one experiment at a time

I needed more practice with articles, adjective endings and pronouns. So I made browser exercises for myself and the people I learn with. Trying them together taught me as much about building useful tools as it did about German.

Slot Deutsch A little article practice, made for your phone.

Slot Deutsch in English with B2 selected, a 4:0 score, Gemütszustand translated as state of mind, and the previous word Mann

Adjektivendungen

Deutsche Pronomen

Small experimentAdjective EndingsPractice adjective endings in sentence context. Small experimentGerman Grammar PracticeRepeat word order and key grammar patterns. Small experimentDeutsche PronomenTrain cases and context-based pronouns. Small experimentSlot DeutschBuild article recall with immediate feedback.

Made for practice, improved through feedback from fellow learners.

Team projects

Things we built together

Team projectTeam Lead · Backend

Link Shortener Service

Five people, one link shortener and plenty of decisions to make together. I wrote backend code and coordinated the team. Shared Postman collections, pull requests and code reviews helped us work on the same service without losing track of each other.

Java 21 · Spring Boot · REST · JWT · PostgreSQL · Flyway · Docker Compose

View repository

Read what I contributed

I combined hands-on backend work with team coordination: clarifying tasks, reviewing pull requests and creating a repeatable API-testing workflow the whole team could use.

Team projectScrum Master · Backend

Multi-Currency Telegram Bot

Our team built a Telegram bot for checking exchange rates. My part included connecting the bank APIs and caching their responses. I liked this problem: the same question shouldn’t need a fresh request to the bank every time.

Repeated user requests→cached response→bank API refreshed only after TTL expiry

Java 21 · TelegramBots · REST · Gson · Gradle · JUnit · Mockito

View repository

Personal projectDesigned · Built · Deployed

QuizForger

I wanted a way to turn learning material into something people could play with. QuizForger began as my CS50 web project. You can create a quiz yourself or bring questions from an AI tool through a JSON import, then edit and share them.

Friends and people from my language course tried it and helped me see what needed changing. I built and deployed it myself, and keep it running in my Raspberry Pi homelab.

A look under the hood

HTML, CSS and JavaScript for the browser interface
Python and Django for the application logic
SQLite for storing quizzes and attempts

Try QuizForger View source

The person behind the projects

Different chapters, the same curiosity

My route here went through industrial automation and running a language centre. Working with equipment made me curious about systems. Working with learners taught me to listen, explain and notice when something that seems obvious to me isn’t obvious to someone else.

Those experiences still meet in my projects: something needs explaining, practising or simplifying, and I start wondering whether I can build something to help. My technical communications work at Smart Industry Group keeps me connected to industrial software, too.

Follow the question until the system makes sense.

If I keep repeating it, I’ll probably build a tool for it.

Let someone else try it. Then listen.

AI in my workflow. I use Codex and Claude for code analysis, refactoring, tests and documentation. I treat generated code as a proposal: it still needs to be understood, reviewed and verified.

Learning and certification

GoIT Java Developer Program

Completed October 2025

The conversation can continue

What are you working on?

Tried one of the tools? Found something confusing? Or building something of your own? I’d enjoy hearing about it.

LinkedIn GitHub

Built and self-hosted from my Raspberry Pi homelab. Last updated: September 2026.