Full-stack developer aka dualfroz
I'm a full-stack developer from Kraków. I build products end to end - infrastructure, backend, and the interface on top - most of them under VulCode, a developer studio set on building a strong Polish brand in IT. I care about systems that are honest about what they actually do.
What is left of 7 573 499 written: 200 906 769 characters, ~402 novels, ~26.9 km printed.
~366 changed lines per commit, ~14.5 commits per active day. Last 30 days: 3 803.
All of git.vulcode.com, with copies of the open source projects I write for. 105 are my own, in 26 languages.
First lines of code in 2020, latest commit on 2026-10-25. 1 318 429 lines taken back out along the way.
Short answers, no filler - the fastest way to know how someone works.
What drives you?
A healthy fear of shipping bad code. It keeps me reading my own diffs as if someone else had written them.
How a first website turned into a stack of products.
I wrote my first lines of code in 2020. It started with simple static sites, nothing serious, but every next one taught me something the previous one did not. Everything after this was me chasing that same feeling of something I wrote working for the first time.
Ran SCP:SL game servers and wrote custom addons for them in C#. Those addons grew into Nebula, a plugin suite whose flagship tool handles server moderation and analytics. My first real users, and my first taste of shipping to people who complain when it breaks.
At MatHost I handled technical support across hundreds of tickets: game servers, Discord bots, Pterodactyl, and over time marketing as well. Every ticket showed another way hosting can break, and that is where I learned what it really looks like from the inside.
In 2024 I started freelancing heavily. I built projects for people end to end, with a focus on architecture and infrastructure rather than one-off features.
VulCode is the Polish software house I run: websites, panels and dashboards, applications and scalable platforms. The numbers below come live from my repositories.
Aphrodi is a branding, digital and marketing studio. It owns the visual language and strategy that complement what VulCode builds in code.
I contribute to open source projects used by millions of people, from developer tools to libraries. Some of my own tools, like vulp, are open too.
I build my own SaaS products: Flaem, a hosting platform with a Rust and Elixir core, Atrium for hotels and accommodation, and Lokal for restaurants.
Measured in lines across every repository - not self-rated stars.
| Language | Lines | Projects | % |
|---|---|---|---|
| TypeScript | 3 152 617 | 51 | 51.7 |
| Rust | 1 171 412 | 11 | 19.2 |
| Go | 343 647 | 13 | 5.6 |
| Kotlin | 206 250 | 7 | 3.4 |
| C# | 162 872 | 8 | 2.7 |
| JavaScript | 144 036 | 39 | 2.4 |
| Other (20) | 918 236 | - | 15.1 |
Counted by my own ghstats - last snapshot available, from 26/10/2026.
I do not tie myself to one language, the tool has to fit the job. Most days that is TypeScript, and when something has to hold up under load, Rust and Go.
TypeScript is my default. My frontends, backends and panels run on it, because in most projects the language is not the hard part.
TypeScript
frontends, backends and panels
3 152 617 lines
Where speed and control over memory matter. Rust carries the Flaem core, the Gyred server and vulp, Go runs the Plazer backend and the Lunatic Chess server, and Elixir keeps an eye on Flaem nodes.
Almost every service runs in a Docker container behind Nginx. Data lives in PostgreSQL, in smaller projects in SQLite, and Redis works as the cache.
Browser
React, TailwindCSS
Dockera container under almost every service
Reverse proxy
Nginx
Backend
Node.js, Go, PHP, Python
Data
PostgreSQL, SQLite, Redis
Kotlin for Android, Swift for iOS. Along the way Kotlin got my own database engine and Swift a Scheme interpreter.
Android
Kotlin
206 250 lines
7 projects
iOS
Swift
116 812 lines
4 projects
First came C# plugins for SCP:SL servers, which grew into Nebula. Today it is Lua scripts, a voxel engine in C++ and graphics for whatever I build.
C#
This is where it all started. I ran SCP:SL servers and wrote my own addons for them, which grew into Nebula, a plugin suite whose flagship handles server moderation and analytics. Later it also got retro console emulators written from scratch and a homelab dashboard in Avalonia.
162 872 lines8 projects
Lua
Lua and TOML describe the pieces with abilities, the maps and the area effects in Lunatic Chess, online chess with modifiable rules running on an engine written in Go. I also wrote a roguelike game in it, with a bestiary and gear.
32 053 lines2 projects
C++
C++ holds my voxel game engine with its own renderer. I have wanted to make my own game since I was a kid, and here it grows from the lowest layer up, with no ready-made engine underneath.
57 275 lines2 projects
Blender
In Blender I model and render 3D for the things I build myself. I also make 3D models at Aphrodi: a product from any angle in photorealistic renders, ready for the store and for ads.
Photoshop
Photoshop is where I make raster graphics for my projects. Graphics are also a separate part of my work: at Aphrodi I do brand identity, illustrations and social media graphics.
DaVinci Resolve
In DaVinci Resolve I edit video for whatever I make. At Aphrodi I also edit clients' footage: pacing, colour, sound and captions, exported for every platform.
In each of these I built one specific thing, to understand how it works from the inside.
I write interfaces in TypeScript on React and style them with Tailwind, from websites to panels. Plain JavaScript stays where the browser is enough on its own, like on this site, which has no build step at all.
Outside the daily set: Bootstrap (responsive UI, since replaced by Tailwind), Vue (a UI framework), Angular (a frontend framework).
Most backends are Node.js with Express and Prisma. Go comes in where performance and simplicity matter, like in Plazer and the Lunatic Chess server. PHP runs the backend of this site, and Python does scripts, bots and monitoring.
Outside the daily set: ASP.NET Core (.NET APIs), Flask (smaller Python services), Django (large Python web apps).
Rust gets the things that have to be fast and under full control of memory: the Flaem core, the Gyred server and the vulp terminal app. Elixir on OTP keeps an eye on Flaem nodes. At the very bottom is a hobby operating system in C, with assembly startup code, that boots in QEMU.
For phones I write native: Kotlin on Android, Swift on iOS. Kotlin also got a relational database engine of my own, and Swift a Scheme interpreter.
It started with games: C# plugins for SCP:SL servers that grew into Nebula. Today it is Lua scripts for Lunatic Chess, a voxel engine in C++, and the graphics, models and editing around what I make.
Outside the daily set: Unity (a game engine), Godot (an open source game engine), Unreal Engine (3D games).
SQLite through Prisma by default, because a smaller project needs nothing more. When a project grows, like Plazer and Flaem, PostgreSQL comes in and Redis acts as the cache. MySQL stayed from hosting panels and Pterodactyl.
Outside the daily set: MongoDB (document NoSQL database), ClickHouse (real-time analytics), Cassandra (distributed, high availability).
Almost every service of mine runs in a container on Docker Compose, behind Nginx as the reverse proxy. I manage over a hundred repositories with Git and vulp, and write code in VS Code.
Outside the daily set: Kubernetes (orchestration at scale), Grafana (metrics dashboards), JetBrains IDEs (JetBrains IDEs).
Languages where I built one specific thing to understand how it works inside: a key-value store in Zig, a SAT solver in Haskell, an exchange in Solidity, a language of my own in F#.
Lines and projects for languages are measured across my repositories.