Senior Java Developer (Kafka)

#vacancy #Kafka #Java #job #Poland ##Senior #backend #Kraków

Twinslash

We’re Hiring: Senior Java Developer (Kafka)

Location: Hybrid — Kraków, Poland

Start: ASAP

We are looking for a Senior Java Developer to join an international team building high-performance, cloud-native backend solutions and real-time event-driven platforms.

Key Skills

• Core Java
• Apache Kafka & Kafka Streams
• REST APIs
• Test-Driven Development (TDD)
• MongoDB
• Google Cloud Platform (GCP)
• Distributed Systems & Scalable Architectures
• Agile Development
• Fluent English (B2+)

Responsibilities

• Design, develop, and maintain high-performance backend services using Java
• Build and enhance event-driven, real-time streaming solutions with Apache Kafka
• Develop and maintain robust REST APIs supporting critical business processes
• Contribute to cloud-native applications running on Google Cloud Platform (GCP)
• Write clean, scalable, and maintainable code following TDD principles
• Collaborate with architects, business analysts, and distributed engineering teams
• Support platform modernization, scalability improvements, and performance optimization
• Participate in technical design, code reviews, testing, and production support
• Investigate and resolve complex technical and production issues
• Promote engineering best practices and continuous improvement across the team

Requirements

• Strong commercial experience with Core Java development
• Hands-on experience with Apache Kafka and Kafka Streams
• Experience designing and developing REST APIs
• Strong knowledge of Test-Driven Development (TDD) and automated testing
• Experience working with MongoDB
• Experience developing cloud-native solutions on Google Cloud Platform (GCP)
• Strong understanding of distributed systems, software design patterns, and scalable architectures
• Ability to solve complex technical problems independently
• Experience working in Agile, globally distributed teams
• Strong communication and collaboration skills
• Fluent English (B2+)

Nice to Have

• Scala
• Spring Boot, Micronaut, Spring WebFlux
• Terraform, Docker, GKE, Cloud Run
• CI/CD tools such as Jenkins or TeamCity
• Experience with real-time, high-throughput systems
• Background in capital markets, trading systems, risk management, or market data platforms

Work Format

Hybrid position based in Kraków, Poland.

Interested or know someone who fits? Reach out directly:

Skills

• Java
• Apache Kafka
• Kafka Streams
• REST APIs
• MongoDB
• Google Cloud Platform
• GCP
• Test-Driven Development
• TDD
• Distributed Systems
• Scala
• Spring Boot
• Micronaut
• Spring WebFlux
• Terraform