Auf Deutsch wechseln

Hey there! I’m

Oliwier Urbanski

Backend Engineering, LLM Systems & RAG, Test Automation, Software Engineering Apprentice

Based in Berlin, Germany.

Software Engineer. A passionate developer who loves crafting innovative solutions.

Get in Touch

About Me

Backend systems, language models, and the question of how you verify either of them reliably.

Background

I am a software engineering apprentice at STRATO, part of the IONOS Group, in Berlin. The apprenticeship started in September 2024 and, on a shortened track, ends in January 2027. My vocational school is OSZ IMT.

I started in quality assurance: test automation for a macOS desktop client, built up inside a newly formed project team. Since then my focus has shifted to backend systems that work with language models — extracting content, making it retrievable, and the question of how you verify any of that reliably.

That question is the common thread. A system built on language models is rarely clearly broken or clearly fine — it is usually right. Working out which cases it is not right for is the work that interests me.

From February 2027 I am available full-time, in Berlin or remote.

  • LLM systems

    Integrating an LLM gateway over REST/JSON including authentication, plus evaluations that run the same scenario repeatedly.

  • Backend & data

    Services in Python and FastAPI, data in PostgreSQL, caching via Redis, running in Docker containers.

  • Test automation

    Automated functional and regression tests for a macOS client with Appium and Selenium, including SSO sign-in.

  • Built solo

    Final project built alone over roughly four months: backend and frontend, two data sources merged and made searchable.

Skills & Expertise

Technologies I have worked with in real projects — not ones I find interesting.

Backend & APIs

  • Python
  • FastAPI
  • REST/JSON
  • PostgreSQL
  • Redis
  • Docker

LLM systems & RAG

  • RAG
  • Embeddings
  • Retrieval
  • LLM-Gateway-Integration
  • LLM-Evaluation
  • Mehrfachdurchlauf-Evaluationen

Test automation & QA

  • Appium (mac2)
  • Selenium
  • Playwright
  • Regressionstests
  • SSO-Flows
  • Jira

Frontend & mobile

  • TypeScript
  • React
  • React Native
  • Next.js
  • CSS

Practice & tooling

  • Git
  • UML-Aktivitätsdiagramme
  • Testfall-Dokumentation
  • Code Review

Professional Journey

Apprenticeship and vocational school.

  1. Apprenticeship, IT specialist for application development (IHK)

    STRATO (IONOS Group)

    Period: Sep 2024 – Jan 2027Location: Berlin

    Shortened apprenticeship with a backend focus. Initially quality assurance and test automation, later backend development on an internal system built around language models.

    Key achievements & skills
    • Built automated functional and regression tests for a macOS desktop client with Appium and Selenium, including SSO sign-in.
    • Integrated an LLM gateway over REST/JSON including authentication into the QA tooling.
    • Designed multi-run evaluations that check the same scenario repeatedly — because a single green run proves nothing with language models.
    • Introduced Git-based version control and documented test cases in a newly formed project team.
    • Python
    • FastAPI
    • PostgreSQL
    • Redis
    • Docker
    • RAG
    • LLM-Evaluation
    • Appium
    • Selenium
    • Git

  2. Vocational school, OSZ Information and Medical Technology

    OSZ IMT

    Period: Sep 2024 – Jan 2027Location: Berlin

GitHub Activity

Public contributions over the last twelve months.

72 contributions in the last year

lessmore

Let's Connect

I'd love to hear from you — by email or on LinkedIn.

Location
Berlin, open to remote
Languages
German (native), Polish (native), English (fluent)