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Hi, I'm Sebastian Witasik

Hi, I'm Sebastian Witasik

Developer that thinks. Code that behaves.

I’ve been writing code for more than half of my life. These days, I thrive where others slow down — fixing broken delivery flows, restoring trust in production, and improving what others accept as 'just the way it is'.

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About Me

I started coding at 11 — not because someone told me to, but because I saw potential and used the tools I had to make it happen. Since then, I have shifted across languages — C++, Java, AutoIt, PHP, JavaScript — whatever best solved the problem at hand.

At 13, Minecraft hit — and that changed everything. I wasn’t just playing; I was hosting servers, writing plugins, managing uptime, debugging crashes, responding to users, and dealing with version conflicts. I didn’t realize it at the time, but I was learning deployment, operations, and delivery — in the most fun way possible. Minecraft was my first real production environment.

Pixel art of a Minecraft-style Villager holding a laptop

Later, I formalized it all — completing my engineering degree with honors, a year ahead of schedule (Pomeranian University in Słupsk, 2018–2021). I entered the market during COVID, already accustomed to pressure-driven, user-facing systems.

Today, I focus on backend engineering. I stay calm in chaos, ruthless in logic, and deliberate in execution. I bring structure where teams are stuck, improve systems where things break, and help people deliver software they can trust again.

I still love to build. That has never changed. These days, I just create with better tools — and higher stakes.

My Experience

LSN

Java Software Engineer | March 2021 — Present | Sopot, Poland

  • Building systems for the insurance industry with focus on high-availability and performance.
  • Developing and optimizing REST APIs and SOAP WebServices for external partners.
  • Enhancing database communication efficiency for better system responsiveness.
  • Strong backend development with Java and relational databases.

LSN

Junior Java Software Engineer | July 2020 — February 2021 | Sopot, Poland

  • Supporting and extending APIs for external partners in the insurance domain.
  • 85% new feature implementation, 10% analysis, 5% testing support (API and automation).
  • Involvement in system deployments and API enhancements.

LPP S.A.

Android Intern | July 2019 — September 2019 | Gdańsk, Poland

  • Android development internship in one of Poland's largest fashion companies.
  • Worked on real-world mobile applications and participated in the development cycle.
5+ years in commercial Java development
4+ backend commercial systems built from scratch
4x awarded internally for exceptional performance
14+ years of hobby programming experience
500,000+ users had contact with my work and were happy
Visual enhancement

My Education

Logo of Pomeranian University in Słupsk

Pomeranian University in Słupsk

Engineer (B.Eng.), Computer Science

2018 – 2021

  • Graduated with distinction (GPA: 5.0)
  • Finished a year early (standard: 3.5 years, mine: 2.5)
  • Founded and led the DevCrew student club

I wasn’t looking for prestige — I wanted practicality. This university offered a unique curriculum shaped by actual IT business owners from the region. It wasn’t theory-heavy — it was designed to prepare us for real-world work.

That meant diving deep into algorithms and databases, but also learning C#, Java, and PHP in real project settings. We touched every layer of modern computing: from network design to operating systems, computer architecture, and even embedded systems and simple circuits.

Through founding DevCrew, I learned to organize events, manage people, listen actively, and coordinate group work. It wasn’t just about leading — it was about learning how to create space for others to grow.

My working stack

Core Stack

Java
Spring
PostgreSQL
MsSQL
Redis
RabbitMQ
Maven
JUnit
Mockito
Git
IntelliJ IDEA
ApiDog

Used Occasionally

TypeScript
JavaScript
Python
bash
Docker
Jenkins
GitHub Actions
Nginx
Elasticsearch
Logstash
Kibana
Prometheus
Grafana

Hobby / Personal Projects

Astro
Tailwind CSS
Dart
Flutter
Kotlin
Gradle
C++
C#
PHP

Why do you want me on your team

01

Independent execution

I don't need micromanagement – I take ownership and deliver on my own initiative.

02

Stepping in when needed

When a PM is unavailable, I can coordinate priorities, team flow and communication.

03

Consistency and accountability

I ensure alignment between scope, execution and delivery quality.

04

Reliable in high-pressure moments

When things go wrong, I step up, take responsibility and solve it.

05

Organizational awareness

I notice broken workflows and suggest concrete improvements.

06

Business-aware mindset

I make decisions in the context of the product and client needs – not just specs.

07

Problem solver by default

I escalate only when necessary – If I have the tools, I solve it myself.

08

Clear decision-making

I don’t defer when it matters – I decide, act, and own the result.