Hi, my name is

Sebastian Ziemianski.

I'm a |

I build scalable systems and digital products — from backend APIs to full-stack apps. Founder of carsite24, building IT solutions for automotive dealerships. Studying Informatics at Fontys (Data Science & AI).

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About Me

Hello, I'm a dedicated student and founder with over 4 years of hands-on experience in software development and building real products. I focus on backend systems, clean architecture, and bringing ideas from concept to deployment.

I'm an Informatics student at Fontys Venlo (2024–2028), specializing in Data Science & AI. I previously studied Computer Science at RWTH Aachen (2022–2024) and switched to a more practical, project-based university to deepen my applied engineering skills.

My work centers on backend systems, databases, and scalable architectures. I have an entrepreneurial mindset and enjoy building real products while studying.

Sincerely,
Sebastian

Education

My Education

Fontys University of Applied Sciences

Informatics · 2024 – 2028 (expected)

Data Science & AI

Applied machine learningDatabase systemsSoftware engineeringAgile developmentPractical system design

RWTH Aachen University

Computer Science · 2022 – 2024

Algorithms & data structuresMathematicsSystem fundamentals

Maria-Sybilla-Merian-Gymnasium

Abitur · Aug 2014 – Jun 2022

Grade (Germany): 2.0

Certificate for outstanding achievements in Computer Science

Experience

My Experience

Founder & Software Developer

Current

carsite24 · Since January 2026

IT solutions for automotive dealerships: custom websites, management systems, SEO optimization, and system integrations.

Currently building a proprietary dealership management system:

Vehicle data aggregation (DMS like cargate360 integration)
API-based vehicle imports
Automated publishing to Mobile.de, AutoScout24 & dealership websites
Centralized inventory management
PostgreSQL as single source of truth
Automated sync via cron/webhooks

Next.jsReactTypeScriptNode.jsPostgreSQLPrismaAPI integrations

Automotive Operations & IT Support Assistant

GS Automobile Rheinland · 2023 – Present

Managed vehicle listings & digital systems
IT support & troubleshooting
Vehicle documentation verification
Automotive photography & online publishing

Working Student IT Support and Web Management

IPE Immobilienprojektentwicklung · 2024 – 2025

Website management (CMS / WordPress)
On-site IT support
Technical troubleshooting

Projects

My Projects

gsauto.de

Automotive Dealership Website

Dynamic vehicle inventory
Structured data for SEO (JSON-LD)
Dynamic sitemap (one URL per vehicle)
DMS integration (cargate360)
Lead forms & clean vehicle filtering

Technologies used

React / Next.jsTypeScriptTailwind CSSNode.jsAPI routesPostgreSQL

University ERP System

Full-Stack Information System — Fontys Project

PostgreSQL database
Layered architecture
REST API
Svelte frontend
Test-driven development
Agile sprint structure

Technologies used

SveltePostgreSQLREST APILayered Architecture

Skills

My Skills

Frontend

ReactNext.jsTypeScriptJavaScriptTailwind CSSHTML5CSS3SvelteVue.jsReduxFramer MotionResponsive DesignAccessibility (a11y)

Backend & APIs

Node.jsExpressREST APIsGraphQLAPI DesignPrismaPHPServerlessWebhooksJSON-LDStructured Data

Databases & Data

PostgreSQLSQLData ModelingMigrationsIndexingData Science (applied)ETLJSONRelational Design

DevOps & Deployment

GitGitHubDockerVercelVPSLinuxCI/CDNginxCronEnvironment VariablesLogging

Tools & Workflow

VS CodeFigmaChrome DevToolsPostmannpmpnpmAgileScrumJiraTechnical SEOLighthouse

Languages & Other

GermanEnglishSystem ArchitectureTDDDocumentationCode ReviewClean CodeProblem Solving

Contact

Contact Me

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