Senior Java Software Engineer

SIX; Warszawa; Hybrid; PLN 220,000 - 260,000; Full time

Job summary

SIX is seeking a Senior Java Software Engineer to advance our cloud-based platforms in a hybrid role. You’ll influence architecture, drive technical excellence, and work with a diverse global team to design high-performance, scalable solutions and modernize application landscapes.

You will own critical backend systems using Java 17/21, Kubernetes/OpenShift, and microservices, while collaborating across product, engineering, and ops teams in a hybrid environment.

Qualifications

• Experience developing large-scale distributed backend applications in Java 17/21.
• Hands-on with Kubernetes/OpenShift, Docker/Podman, and cloud-native development.
• Strong knowledge of REST APIs, JSON, Kafka, and event-driven architectures.
• Experience in designing and operating microservices.
• Advocate of automated testing, CI/CD, observability, and documentation.
• GitLab and modern delivery pipelines experience.
• Excellent communication in English.
• Nice to have frontend tech: JavaScript/TypeScript.

Responsibilities

• Drive Architecture & Design for a scalable, secure application landscape.
• Build innovative solutions using modern Java technologies and cloud-native practices.
• Collaborate with product managers, architects, business stakeholders, and engineers to deliver outcomes.
• Champion technical excellence across performance, data processing, and reliability.
• Own the full lifecycle from design to deployment and support.
• Support DevOps practices and production service enhancements.

Skills

Java 17/21

Kubernetes/OpenShift

Docker/Podman

REST APIs

Kafka

Microservices

CI/CD

GitLab

Observability

JavaScript/TypeScript

Job description

Are you passionate about building robust, scalable software that powers critical financial services? Do you thrive in an environment where you can influence architecture, drive technical excellence, and work with modern cloud-native technologies? If so, we'd love to hear from you.

As a Senior Java Software Engineer, you will play a key role in the evolution of our cloud-based platforms, working alongside a diverse international team of engineers, architects, and product experts. You will help design and deliver high-performance solutions, modernize application landscapes, and contribute to products that create real value for our customers.

This role offers the opportunity to work with modern technologies, take ownership of technical decisions, and collaborate in a flexible hybrid work environment.

What You'll Do

Are you passionate about building robust, scalable software that powers critical financial services? Do you thrive in an environment where you can influence architecture, drive technical excellence, and work with modern cloud-native technologies? If so, we'd love to hear from you.

As a Senior Java Software Engineer, you will play a key role in the evolution of our cloud-based platforms, working alongside a diverse international team of engineers, architects, and product experts. You will help design and deliver high-performance solutions, modernize application landscapes, and contribute to products that create real value for our customers.

This role offers the opportunity to work with modern technologies, take ownership of technical decisions, and collaborate in a flexible hybrid work environment.

• Drive Architecture & Design: Contribute to the design and evolution of a complex application landscape, ensuring solutions are scalable, secure, and maintainable.
• Build Innovative Solutions: Develop and enhance business-critical functionality using modern Java technologies and cloud-native engineering practices.
• Collaborate Across Teams: Partner with product managers, architects, business stakeholders, and fellow engineers to deliver impactful outcomes.
• Champion Technical Excellence: Lead initiatives focused on performance optimization, data processing, system scalability, reliability, and code quality.
• Own the Full Lifecycle: Contribute throughout the software development lifecycle, from design and implementation to deployment, support, and continuous improvement.
• Support DevOps Practices: Actively participate in operating and enhancing production services as part of a DevOps culture.

What You'll Bring

• Strong Java Expertise: Proven experience developing large-scale, distributed backend applications using Java 17/21.
• Cloud-Native Engineering: Hands-on experience with Kubernetes/OpenShift, container technologies (Docker/Podman), and cloud-based application development.
• API & Event-Driven Systems: Solid understanding of REST APIs, JSON, Apache Kafka, and event-driven architectures.
• Microservices Architecture: Practical experience designing, building, and operating microservice-based solutions.
• Modern Engineering Practices: Strong advocate of automated testing, code reviews, CI/CD, observability, and technical documentation.
• Version Control & DevOps Tooling: Experience working with GitLab and modern software delivery pipelines.
• Excellent Communication: Strong collaboration and communication skills, with professional proficiency in spoken and written English.
• Nice to Have: Experience with JavaScript/TypeScript and modern frontend technologies.