Hoogstraten, BE · CET Software Engineer · backend & full-stack, AI-native

Sybren
Van Gastel.

Software engineer. Knows when to move fast and when to slow down and get it right.

I'm Sybren, a software engineer based in Belgium. I move comfortably between early-stage exploration and production-grade engineering. Pragmatic by default, AI-native by habit and flexible in order to get the job done.

See selected workMy Work → Reach out on LinkedInLinkedIn ↗

01 WORK 2020 → PRESENT

Different stacks, different teams, same way of working.

01 / 03

Digipolis Antwerpen

Software Engineer · Consultancy via 3-it / Upcore · Current client

I work on multiple software projects for the police department of Antwerp, each a different shape of problem, from rapid prototypes to production-grade systems.

Innovation team SEP 2025 → PRESENT

Building rapid AI-powered prototypes for internal police use, including RAG-based chatbots, automated data processing pipelines and a speech-to-text system for transcribing interviews and recordings.
Responsible for the full prototype lifecycle: from concept and development to limited rollout and iteration based on user feedback.

PythonReactLocal LLMs

FOCUS OCT 2024 → PRESENT

Designed and built a backend system unifying legacy data sources into a search-optimised layer, with enrichment pipelines covering geocoding, deduplication, clustering and translation.

.NETC#

TJILP DEC 2022 → SEP 2024

Backend development for a modular policing platform, building modules for case management, OSINT data integration, police report processing and data analysis.
Owned technical decisions on the .NET backend, working closely with a platform architect in a cross-functional team.

.NETC#PythonABP Framework

02 / 03

3-it / Upcore

Software Engineer · Current employer

I joined 3-it as an intern, stayed on the team, and have been with them ever since. Since late 2022 I've been dispatched to Digipolis Antwerpen as a consultant through their consultancy branch, Upcore. Before that, I shipped two internal projects with the team directly.

CRM modernisation & cloud migration MID 2022 → DEC 2022

Modernised a legacy CRM by upgrading the full stack and integrating a UI library, using a reverse proxy strategy to ensure a seamless transition without loss of functionality.
Built an automated email allocation pipeline replacing a fully manual workflow, handling mailbox delegation, CRM linking and mail archiving.
Migrated the on-prem infrastructure to Azure.

.NETAngularAzure

Task Scheduling Tool FEB 2022 → MID 2022

Built an internal web app for support engineers to schedule and manage recurring client tasks across a team, replacing ad-hoc calendar reminders.

.NETAngularAzure

03 / 03

Katz

Software Engineer

I started at Katz digitalising the outdated assessment tooling they used in-house. A few months in I joined IForYou, the HR product they were spinning up as a startup, and ended up working across the whole thing: analysing features with the team, prototyping the web app, then building it in Angular against Java microservices.

I For You · HR platform NOV 2020 → FEB 2022

Core team member contributing across the full product lifecycle: from feature analysis and architecture to implementation.
Led a 3-person frontend team responsible for the UI framework and component library.

AngularTypeScriptJava

Assessment Platform JUL 2020 → NOV 2020

Converted forms and spreadsheet-based assessment tools into a unified web platform with automated processing, eliminating manual preparation between tests.

DjangoPython

02 WORKING STACK WHAT I REACH FOR FIRST

Comfortable across the stack. Strongest on the backend and integration layer.

Backend

.NET / C#DAILY
PythonDAILY
JavaPRIOR & PERSONAL

Frontend

ReactDAILY
TypeScriptDAILY
AngularPRIOR

Tooling & Platforms

DockerDAILY
Claude CodeDAILY
Local LLM stacksOFTEN
AzurePRIOR

Standards, libraries and infra rotate with the project. This list is what I'm currently spending the most time in.

03 ABOUT WHO YOU'RE HIRING

Most of the value I bring isn't the code. It's the conversation before it, and the long-term decisions around it.

I'm a software engineer based in Hoogstraten, Belgium. I graduated Applied Computer Science summa cum laude, started shipping real product during my bachelor's at a startup, and have spent the years since building backend systems and full-stack tools as a consultant.

I'm vocal in meetings, but solution-first. I'd rather walk in with a trade-off and a recommendation than a list of problems. When the room disagrees, I look for the pragmatic middle and propose it.

Outside work I keep building things I care about, like a long-running gaming community I help run and the occasional side experiment with new AI tooling. The work stays interesting because I keep poking at it on my own time.

in Reach out on LinkedIn ↗

SYBREN VAN GASTEL HOOGSTRATEN · BE

Based in Hoogstraten · Antwerp, Belgium

Education Applied Computer Science · bachelor

Working since 2020 · startup & client work

Languages Dutch · native English · fluent

Working style Pragmatic · get-it-done

Open to work in Antwerp province · or remote

04 OFF THE CLOCK WHAT I BUILD ON MY OWN TIME

Majestum Kingdoms

Live · ongoing

A custom RPG / survival gamemode I've been building for years, focused on world-building and PvX content. I operate at every level: maintaining the server infrastructure, shaping the concept, developing plugins, running communication and managing a small team of contributors.

JavaServer infraGame designCommunity

Code Clarity

Archived

An early experiment with local-LLM-powered code review, built before today's generation of coding agents existed. Shelved once the ecosystem caught up, but a useful early bet on where the workflow was going.

.NETReactLocal LLMs