Java Backend Engineer for Public Sector APIs & Systems

Billennium; Województwo śląskie; On-site; PLN 140,000 - 210,000; Full time

Benefits offered by this job

Udemy for Business

Private medical care

Multisport card

Language lessons

Shopping vouchers

Team-building events

Job summary

Billennium is seeking a Java Backend Developer to join a major public-sector project focused on building large-scale IT systems. You will design and implement scalable backend services using Java, APIs, and relational databases, while collaborating with international teams and adhering to scaled Agile practices.

The role emphasizes delivering robust backend solutions for financial programming, public procurement, or grant management, with a focus on modern messaging and API-driven architectures.

Qualifications

• Higher education in ICT/STEM with a diploma (minimum 3 years of university education).
• At least 2 years of professional Java backend experience after graduation.
• Proven API design and backend development experience.
• Experience with relational databases (Oracle, MySQL) and messaging (Kafka, JMS, ActiveMQ).
• Experience delivering large-scale public-sector IT systems is highly valued.
• Knowledge of scaled Agile methodologies (SAFe or LeSS) and international teams.

Responsibilities

• Design and develop scalable backend solutions using Java.
• Create, test, and maintain APIs and backend services.
• Work with relational databases (Oracle, MySQL) and messaging systems (Kafka, JMS, ActiveMQ).
• Contribute to large-scale public-sector IT projects in an international environment.
• Apply scaled Agile practices (SAFe/LeSS) and drive continuous improvement.

Skills

Java backend development

API design

English proficiency (B2/C1)

Team collaboration

Education

Higher education in ICT/STEM with diploma

Tools

Kafka

JMS

ActiveMQ

Oracle

MySQL

Job description

Billennium is seeking a Java Backend Developer to join a major public-sector project focused on building large-scale IT systems. You will design and implement scalable backend services using Java, APIs, and relational databases, while collaborating with international teams and adhering to scaled Agile practices.

The role emphasizes delivering robust backend solutions for financial programming, public procurement, or grant management, with a focus on modern messaging and API-driven architectures.