Junior Java Software Engineer w Katowice, Polska

We are looking for a Junior Java Software Engineer to join a large-scale internet security protection platform serving millions of end users, providing threat protection, parental controls, and network security for residential and business subscribers. The platform processes high volumes of network traffic and manages real-time security services. You will join a collaborative team with a strong mentorship culture, including principal engineers and senior leads, pair programming, and thorough code reviews, and own the full stack across backend, frontend, and infrastructure.

Implement features and fixes in Java Spring Boot microservices Build React/TypeScript components and manage state with Redux Write unit and integration tests using JUnit, Jest, and Spring Test Support infrastructure automation with Ansible/Terraform Assist with load testing using JMeter Debug issues across distributed microservices Optimize performance in low-latency environments (sub-100ms) Optimize SQL queries in PostgreSQL and Vertica Manage async state in React applications Contribute to improving deployment pipelines and infrastructure as code Participate in code reviews, documentation, standups, and pair programming sessions 0–2 years of experience or a strong academic/project background, with a CS/Software Engineering degree or equivalent Knowledge of Java fundamentals, including OOP, collections, streams, and basic concurrency Knowledge of SQL basics, Git, and understanding of REST/ Learning agility, proactive attitude, and problem-solving skills Collaboration, curiosity, ownership, and communication skills B2+ English proficiency Background in Java/Spring Boot internships and microservices Familiarity with cloud platforms (AWS/GCP/Azure) Familiarity with Agile/Scrum and testing frameworks Knowledge of monitoring tools (Prometheus/Grafana/ELK) Understanding of security basics (OWASP) and networking fundamentals (DNS/ Experience with AI tools (e.g., code assistants, AI-powered development tools)