About

A programmer with long-standing experience in web, mobile, desktop and game products.

My name is Jakub Klementewicz. I run Klementewicz Development and build software across product work, code, infrastructure and maintenance. I prefer projects where the application has to work for real people and real business, not just look good in a presentation.

See projects Technologies

Long-standing: experience in building products and applications
500,000+: users of the Schoolovo product
4: areas covered: web, mobile, desktop and games

Who I am

I combine product thinking with solid software engineering.

I work as a programmer with long-standing experience. My work covers application architecture, backend, frontend, mobile apps, deployments and infrastructure maintenance.

In practice, that means I can join a project more broadly than as someone responsible for a single feature. I help clarify the scope, pick technology, identify risks and deliver a version that can actually evolve.

The main product I built is Schoolovo, but I have also worked on games, mobile apps, business tools and my own products. That makes me look at software through the lens of users, maintenance cost and technical decisions that will either help or hurt a few months later.

Projects

Experience that directly shapes how I work.

These are not empty categories. They come from projects where frontend, backend, mobile, infrastructure and product decisions had to work together.

Schoolovo

An education product used by more than 500,000 people. It includes a mobile app, backend, integrations, maintenance, feature development and ongoing product work.

Rust React Native mobile backend product

Voxelaxy

A game and interactive product project where prototyping, gameplay mechanics, performance, iteration and technical product support are important.

Unity C# games prototype gameplay

Yayco and Glow Glow

Application projects developed with publishing, privacy, simple usage and post-release support in mind. That experience is especially useful in mobile products.

mobile privacy release support

Business systems and web products

Panels, websites, web applications, integrations, automations and tools that help companies handle processes, clients and data with less manual work.

React Next.js WordPress API DevOps

Technologies

The stack I use most often.

I treat technologies as tools for solving problems. A landing page, SaaS app and mobile product with users and subscriptions need different choices.

Backend

Rust Node.js Java PHP C# REST API WebSocket

Frontend and web

React Next.js TypeScript JavaScript HTML CSS WordPress

Mobile

React Native iOS Android Firebase App Store Google Play IAP

Games

Unity C# gameplay prototyping telemetry

Databases

PostgreSQL Cassandra MariaDB Redis Valkey

Infrastructure

Docker Kubernetes k3s CI/CD nginx monitoring backups

How I work

First a sensible scope, then code.

I understand the business goal

Before technology appears, it has to be clear what problem the product solves, who uses it and what success should mean.

I simplify the first version

The first release should be deliverable, testable and ready to extend without unnecessary functionality.

I care about maintenance

Code, deployment, monitoring and backups are part of the product. A good solution keeps working after launch.

Want to check whether I am a good fit for your project?

Send a short description of what you want to build. I will reply with a practical scope and a good starting point.

Write to me