Java Backend Developer - Public Sector APIs

Billennium; Kraków; On-site; PLN 90,000 - 140,000; Full time

Benefits offered by this job

Comprehensive benefits

Career growth

Global collaboration

Innovative environment

Engaging community

Team-building events

Welcome pack

Job summary

Billennium is seeking an experienced Java Backend Developer to join a project for a major European public-sector institution. You will design and implement scalable backend services, APIs, and data flows using Java, Oracle, MySQL, Kafka, JMS, and ActiveMQ within an international team.

The role requires proven experience with API design, RDBMS, and delivering large-scale public-sector IT systems, working in scaled Agile environments (SAFe or LeSS). Proficiency in English (B2/C1) is expected.

Qualifications

• Higher education in ICT/STEM with a diploma confirming at least 3 years of university education.
• At least 2 years of professional experience after graduation.
• At least 2 years of Java backend development experience.
• Proven experience in designing and developing APIs.
• Hands-on with Oracle and MySQL RDBMS.
• Experience with Kafka, JMS, and ActiveMQ messaging.
• Experience delivering large-scale IT systems for the public sector.
• Knowledge of scaled Agile methods such as SAFe or LeSS.
• Experience working for or with an international organization.
• English proficiency at B2/C1 level.
• Certifications are not required.
• Professional experience must be fully documented in Europass CV format.

Responsibilities

• Design and develop scalable backend solutions using Java.
• Design, develop, and maintain APIs and backend services.
• Work with relational databases including Oracle and MySQL.
• Implement messaging and event-driven systems with Kafka, JMS, and ActiveMQ.
• Contribute to large-scale public-sector IT projects.
• Collaborate with international distributed teams.
• Apply scaled Agile methods such as SAFe or LeSS.
• Contribute to analysis, design, implementation, and ongoing improvement.

Job description

Billennium is seeking an experienced Java Backend Developer to join a project for a major European public-sector institution. You will design and implement scalable backend services, APIs, and data flows using Java, Oracle, MySQL, Kafka, JMS, and ActiveMQ within an international team.

The role requires proven experience with API design, RDBMS, and delivering large-scale public-sector IT systems, working in scaled Agile environments (SAFe or LeSS). Proficiency in English (B2/C1) is expected.