Brussels, Belgium

Victor Castelain

Software engineer specializing in applied AI, designing reliable solutions for real-world problems.

About

Hi there!

Victor Castelain on a Brooklyn street, in front of the Manhattan Bridge — Brooklyn, New York

I design and build web applications, APIs and real-time systems, with particular care for reliability and testing. I’m now specializing in applied AI, to bring it into real-world applications. :)

A graduate in computer science from EPFC, I’m pursuing a postgraduate in applied AI at Erasmushogeschool Brussel, where I’m working on machine learning, data science and MLOps.

During a four-month internship at JAK Solutions, I strengthened a SaaS’s regression safety with 65+ Playwright E2E tests wired into CI, built an 8-KPI analytics dashboard and kicked off centralized translation management for the company’s apps with Tolgee, within an Agile team.

I enjoy learning and solving problems: building reliable systems, testing them thoroughly and understanding why they behave the way they do. Outside of code, I like to travel and play sports.

Toolbox

What I build with

Languages

Rust
C#
TypeScript
Java
SQL
PHP
Dart
JavaScript
Python(Currently learning)

Frameworks

Tokio
ASP.NET Core
Entity Framework
Angular
React
Flutter
Riverpod
JavaFX

Databases

PostgreSQL
PostgREST
MySQL
SQLite
Redis

DevOps & testing

Docker
GitHub Actions
Git
Playwright
Swagger

Project management

GitHub
Bitbucket
Jira
Trello
ClickUp
Agile

Real-time & games

WebSockets
Unity
Behavior trees

AI & data

Claude Code
Codex
Machine learning(Currently learning)
RAG(Currently learning)
Multi-agent systems(Currently learning)
Data science(Currently learning)
MLOps(Currently learning)
IoT(Currently learning)
Big data(Currently learning)

Dashed: currently learning

Erasmushogeschool Brussel

Sep 2026 – Apr 2027 · Brussels · about one afternoon a week

Postgraduate in applied AI: moving from classic software to intelligent systems that learn from data.

AI fundamentals and machine learning: understanding, training and evaluating models.
Data science: preparing, exploring and visualizing data.
IoT and big data: collecting and processing data at scale.
MLOps and an AI project: getting a model into production, with a full AI project to wrap it up.

Python
Machine learning
Data science
MLOps

JAK Solutions

Feb 2026 – May 2026 · Brussels

A four-month full-stack internship in an Agile team, on an internal SaaS: automated tests, an analytics dashboard and centralized translations.

A 65+ test Playwright E2E pipeline wired into GitHub Actions CI, so every release walks through Cobria’s critical flows first.
An analytics dashboard with 8 KPIs, date range filters, country segmentation and Excel export.
Centralized translations with Tolgee: kicked off the integration to manage the translations of the company’s apps in one place.
Agile practice: two-week sprints, standups and code reviews with the team.

Playwright
GitHub Actions
React
.NET
Redis
Tolgee

EPFC

Sep 2023 – Sep 2026 · Brussels

Bachelor of Computer Science: development of complete web, desktop and mobile applications, databases, networks and management, validated by a thesis.

Final-year project: The Rulers, a co-op colony game with an authoritative Rust server running at 20 ticks/s (see Work).
Integration project, web and mobile: the shared expenses app in a team of three, with a C# API and an Angular front end deployed with Docker (see Work), plus a Flutter mobile app and a PHP MVC web app.
Desktop and architecture: a Java/JavaFX spreadsheet in MVVM, with its own formula engine.
Networks, computer architecture and management: courses complementing software development, as part of the computer science degree.

C#
Java
TypeScript
Rust
SQL

Selected work

Four projects worth a closer look

01 · Feb 2026 – Oct 2026 · Game & system

The Rulers

Co-op colony sim, authoritative Rust server

Two players, one colony, and a server that always has the final say.

An authoritative Rust server on Tokio: a 20 ticks/s game loop and shared state guarded by Arc/Mutex.
Two Unity clients connected over WebSockets and kept in sync in real time.
Autonomous agents driven by behavior trees.
PostgreSQL persistence for the world state and player progress.

Final-year thesis, EPFC

Rust
Tokio
Unity
WebSocket
PostgreSQL

App screenshot: the “Week-end à Rome” group with its expense list, who paid, and the total

02 · Sep 2025 – Jan 2026 · Web

Shared expenses app

Full‑stack C# and Angular web app, Tricount-style

Everyone logs what they paid for the group, and the app works out how much each person still owes or is owed.

Balances computed in decimal on the server: what each person paid minus their share, weighted by split ratios and rounded to the cent.
An optimistic Angular UI: a new expense shows up instantly, then the data resyncs with the API.
Diff-based updates: when a split is edited, the back end only deletes, updates or inserts what actually changed.
Business rules enforced on the server with FluentValidation and controller checks: no date before the group was created, the payer must be a participant, and nobody already involved in an expense can be removed.

Team of three, EPFC

C#
ASP.NET Core 9
EF Core
PostgreSQL
Angular 20
JWT
Docker

Screenshot of the forms app: the form list with search and color filters

03 · Sep 2024 – Jun 2025 · Web

Online forms

A Google Forms-style app built with PHP MVC

Build a form, share it, answer it one question at a time, then see the results as charts.

Answers saved at every step: moving between questions saves the current answer, and an incomplete submission jumps to the first required question left blank.
Post/Redirect/Get everywhere across the answer flow and the dialogs: refreshing the page does not resubmit the form.
Works without JavaScript too: search and filters work in plain PHP, then switch to AJAX when JS is available, with the criteria compressed in the URL.

Team of three, EPFC

PHP 8
MySQL
JavaScript
jQuery UI
Bootstrap 5
Chart.js

Spreadsheet screenshot: cell B4 holds the formula =A4 + B3 and shows 521

04 · Nov 2024 – May 2025 · Desktop

Interactive spreadsheet

Formulas, dependencies and undo/redo in JavaFX

Type =SUM(B2:C3), change a value, and everything that depends on it recalculates on its own.

A hand-written formula parser: a tokenizer and a recursive split by operator precedence that builds a tree of 18 node types (arithmetic, comparisons, logic, range functions such as SUM).
Reactive cascading recalculation: every cell is a JavaFX binding, and a dependency graph automatically invalidates the cells that reference it.
Undo/redo with the Command pattern: two stacks, Ctrl+Z / Ctrl+Y, and menu items enabled or grayed out through bindings.
MVVM architecture on top of the ControlsFX SpreadsheetView, with a custom file format that only saves non-empty cells.

Team of two, EPFC

Java 21
JavaFX
ControlsFX
Maven
MVVM

At a glance

The essentials

Based in

Brussels, Belgium

Looking for

A full-time software or AI role

Available

Right now, full-time

Where

Anywhere in Belgium, on-site, hybrid or remote

Languages

Contact

Let’s build something.

I’m looking for a full-time software engineering or AI role anywhere in Belgium, on-site, hybrid or remote, and I’m open to relocating. Email is the fastest way to reach me, and I reply to every one.

victor.castelain@hotmail.com

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