Sergiusz Jańczura

Sergiusz Jańczura

Java Developer | Poznań

About me

I am a Java Developer with many years of experience in building and maintaining complex backend applications. I currently work at Hummerce (formerly Best.net), where I am responsible for developing a large-scale e-commerce platform powering multiple online shops across different markets. My work involves designing scalable solutions, optimizing performance, and integrating with external systems — including ERP/CRM platforms, payment providers, and marketing tools.

In my free time, I enjoy playing computer games, swimming, and keeping up with the latest tech trends. I’m passionate about creating stable, well-optimized systems that meet the needs of rapidly growing businesses. I also like to explore lower-level programming — currently learning Rust.

Experience

Java Developer @ Hummerce (03.2020 - Current)

Tester @ Hummerce (10.2019 - 03.2020)

Game Tester/Designer @ FabrykaGier (07.2018)

Skills

  • Java
  • Spring Framework
  • Hibernate / JPA
  • PostgreSQL
  • Maven / Gradle
  • RESTful APIs
  • Git
  • Docker
  • Jenkins
  • Gerrit
  • Burp Suite
  • Postman
  • JavaScript
  • HTML / CSS
  • Python
  • Rust
  • CheatEngine
  • Polish (native)
  • English (B2)

Education

Master of Computer Science 2020 - 2021 (Adam Mickiewicz University)

Bachelor of Computer Science 2013 - 2019 (Adam Mickiewicz University)