Senior Java Backend Developer

Quick Facts

• Role: Senior Java Backend Developer

• Focus: High-performance, business-critical backend systems

• Collaboration: Hybrid model (4 days/month on-site in Warsaw)

Description

You will develop and maintain modern backend solutions for a banking environment using Java 21/25, Spring Boot, reactive architecture, microservices, Apache Kafka, and cloud technologies.

Responsibilities

• Design, develop, and maintain backend applications

• Build and evolve microservices-based solutions

• Integrate systems and develop/enhance APIs

• Optimize performance, security, and application stability

• Ensure high code quality through code review, testing, and refactoring

• Analyze business and technical requirements and propose solutions

• Collaborate with the project team during implementation of new functionality

Requirements

• Minimum 5 years of Java development, including Java 21/25

• Minimum 4 years with Spring Boot (2.3/2.4/2.6)

• Minimum 3 years with PostgreSQL and Elasticsearch

• Minimum 3 years with Apache Kafka and knowledge of Kafka Streams

• Microservices architecture and distributed systems knowledge, including design and architectural patterns

• Experience with Spring WebFlux, Spring Cloud Gateway, Reactor Core, Resilience4j, Spring Security, Hibernate, Spring Data, Jersey

• Integration technologies: REST, JSON, SOAP, XML, XSD

• Security mechanisms: PKI, JWT, TLS/mTLS, public key cryptography, digital signatures

• Experience with Docker and Kubernetes

• Cache solutions (Hazelcast, Ehcache) and servers Tomcat and Netty

• Practical SQL, database schema design, transactions, and locking mechanisms

• Monitoring tools: Prometheus, Grafana, Sentry, Loki, Micrometer, Spring Cloud Sleuth

• Developer tools: Git/Gerrit, GitHub, Zuul CI, Maven, Jira, Confluence, IntelliJ

• Experience with code review and refactoring

• Practical use of AI development tools (e.g., GitHub Copilot and MCP)

• Higher education in computer science, mathematics, or related

• English knowledge sufficient for working with technical documentation

Benefits

• B2B model with transparent collaboration approach

• Contract liaison (dedicated contract owner) as main point of contact

• Access to selected trainings, certifications, and conferences (rules set individually)

• Opportunity to join new qualification processes when project timing changes

• Participation in community initiatives (e.g., webinars) and optional activities (sport, training rooms)

• Optional additional services such as private medical care, sports card, insurance, and psychological support

• Cafeteria platform to choose services/products using allocated points