Backend Java developer

b2bnetwork; Warszawa; On-site; PLN 180,000 - 280,000; Full time

Job summary

b2bnetwork is seeking a senior Java backend developer to design, develop and maintain Java applications for our pension and savings products. You will work on tax calculations and investment processing across multiple countries.

You will participate in the full SDLC, mentor peers, and apply OpenAPI/AsyncAPI knowledge, SQL with PostgreSQL, and CI/CD pipelines. Collaboration with financial analysts and a strong emphasis on quality and responsible AI-assisted development are key.

Qualifications

• Must-have Java 21 and Spring Boot experience.
• Proficient with PostgreSQL and relational databases.
• Familiarity with messaging protocols (JMS, MQ).
• Strong Java capabilities with Spring/Hibernate frameworks.

Responsibilities

• Design, develop, and maintain Java applications supporting our savings and investments products.
• Build robust calculation engines ensuring tax compliance across countries.
• Develop support for complex business processes, integrating with tax authorities and generating reports.
• Participate in full SDLC from requirements to deployment.
• Collaborate with financial analysts to translate requirements into technical solutions.
• Mentor other developers, perform code reviews, and promote engineering practices.
• Use AI-assisted development and automation to improve productivity and learning.
• Demonstrate strong collaboration and analytical skills.

Skills

Java 21

Spring Boot

PostgreSQL

Messaging (JMS/MQ)

Hibernate

OpenAPI/AsyncAPI

Git & CI/CD

Design patterns / OO

Collaboration

Job description

Detailed description of work task to be carried out

The consultant will be responsible for developing, enhancing and maintaining our Java-based applications that handle taxation, account management, and investment processing for our pension and savings products.

Key Responsibilities:

• Design, develop, and maintain Java applications supporting our savings and investments products
• Build robust calculation engines that ensure compliance with current tax regulations across multiple countries
• Develop support for complex business processes, integrating with tax authorities, and generating customer facing reports.
• Participate in the full software development lifecycle including requirements analysis, design, coding, testing, and deployment
• Collaborate with financial analysts to translate requirements into technical solutions
• Mentoring other developers, acting as a code reviewer or design sparring partner but also spreading practical engineering practices across the team
• Use AI-assisted development and automation in a responsible way to improve productivity, quality and learning,
• Strong collaboration skills and good analytical skills

Must-have knowledge and experience

• Java 21
• Spring Boot
• Postgres SQL
• Messaging protocols such as JMS, MQ etc
• Strong proficiency in Java and related frameworks (Spring, Hibernate, etc.)
• Experience with relational databases and SQL (PostgreSQL, etc.)
• Knowledge of OpenAPI and AsyncAPI for producing and consuming data
• Familiarity with version control systems (Git) and CI/CD pipelines
• Understanding of software design patterns and object-oriented programming principles