Java Backend Developer

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

We are a global technology company providing IT services and digital solutions to clients around the world. Headquartered in Poland, with offices in Canada, Malaysia, Germany, Switzerland and India, we bring together over 1,700 professionals who share one mission -to harness technology and innovation to make the world run better. At the heart of Billennium is our vibrant and people-centric culture, where everyone’s potential matters. We embrace diversity, inclusion, and flexibility, empowering our employees to grow and thrive. Our values - captured by the acronym TIGER - define who we are and how we work: Trust, Innovation, Growth, Energy, Responsibility – guide us in everything we do.

Role Summary:

Our client is a major European public-sector institution involved in large-scale digital and administrative transformation initiatives.

We are looking for an experienced Java Backend Developer to join a project focused on the development of large-scale IT systems for the public sector.

The ideal candidate should have proven experience delivering complex public-sector systems related to financial programming, public procurement, or grant management. You will work in an international environment, contributing to the design and development of scalable backend solutions using Java, APIs, relational databases, and messaging technologies.

What You Will Do:

• Design and develop scalable backend solutions using Java.
• Design, develop, and maintain APIs and backend services.
• Work with relational database management systems, including:
• Oracle
• MySQL
• Design and implement messaging and event-driven solutions using technologies such as:
• Kafka
• JMS
• ActiveMQ
• Contribute to the development and delivery of large-scale IT systems for the public sector.
• Work on systems related to areas such as financial programming, public procurement, or grant management.
• Collaborate with international and distributed project teams.
• Work according to scaled Agile methodologies, such as SAFe or LeSS.
• Contribute to the analysis, design, implementation, and continuous improvement of backend solutions.

Requirements:

• Higher education in a technical field (ICT/STEM), with at least 3 years of university education confirmed by a diploma.
• At least 2 years of professional experience after graduation.
• At least 2 years of relevant professional experience in Java backend development.
• Proven professional experience in Java backend development.
• Proven experience in designing and developing APIs.
• Practical experience with relational database management systems (RDBMS), including:
• Oracle
• MySQL
• Practical experience with messaging technologies, including:
• Kafka
• JMS
• ActiveMQ
• Documented experience delivering large-scale IT systems for the public sector, particularly in areas related to:
• public procurement,
• Practical knowledge and experience working with scaled Agile methodologies, such as SAFe or LeSS.
• Previous experience working for or within an international organisation.
• English language proficiency at B2/C1 level.
• Certifications are not required.
• Professional experience must be fully documented in the current Europass CV format, including complete employment dates and sufficient information to verify the required duration and scope of experience.

Perks and benefits (our offer):

• Comprehensive benefits - enjoy Udemy for Business, private medical care, Multisport card, veterinary package, language lessons, and shopping vouchers.
• Career growth - access opportunities for professional development and learning, including perks related to our official partnerships with global IT giants: Microsoft, AWS, Snowflake, Salesforce & more.
• Global collaboration - work with a diverse, international team.
• Innovative environment - be part of a forward-thinking and growth-oriented workplace.
• Engaging community – Work with passionate professionals and participate in team-building events, hackathons, and CSR initiatives to make an impact beyond work.
• Team-building events including our company tradition (annual company event in Mazury).
• A pleasant surprise to start your journey with us in the form of a welcome pack.