Senior Java Developer

Senior Java Developer

Location: Kraków, Poland (hybrid – 2 days/week from office)

Contract type: B2BRate: 140–150 PLN/h

Project type: Long-term, enterprise, payments domain

About the project

For one of our global financial clients operating in the payments domain, we are building a new engineering team responsible for delivering a Future State Architecture for payment processing.

The project focuses on creating a lean, reusable payment processing engine that will become the foundation of next-generation payment capabilities. The work is performed in an inner-sourcing model, with a strong emphasis on reuse, modernization, cloud adoption, and high engineering standards, enabling faster delivery of new product features at scale.

Key Responsibilities

• Deliver engineering expertise for future-state payment architecture and next-generation payment processing capabilities

• Design, build, and maintain highly available, resilient, and scalable backend services

• Produce high-quality, well-tested code and ensure all quality gates are exceeded

• Support the transformation and modernization of the existing payment landscape with strong cloud focus

• Actively participate in a wider delivery team contributing to new platform capabilities

• Resolve architectural and development blockers and provide hands-on technical guidance

• Collaborate closely with DevOps teams to enable CI/CD pipelines and DevSecOps practices

  
  

Key Accountabilities

• Set engineering standards and lead by example within the team

• Act as a technical expert, identifying process improvements and preventing systemic issues

• Provide technical solutions to complex business and architectural problems

• Drive architectural decisions aligned with global standards and business strategy

• Maintain awareness of regulatory, security, and data privacy requirements

• Design, implement, review, and optimize systems for performance, resilience, and operational integrity

• Mentor and coach engineers, supporting their technical and professional growth

  
  

Required Qualifications & Experience

• Bachelor’s degree in Computer Science, Engineering, or a related field

• 8+ years of experience as an API Engineer

• Strong experience in API design and architectural documentation (LLDs, gap analysis, data models)

• 5+ years of backend microservices development, application security, authentication, caching, and middleware

• 8+ years of Java experience (Go and/or Rust is a strong plus)

• Expertise in distributed systems, Spring Boot, microservices architecture

• Experience with Kafka, Docker, Kubernetes, service mesh

• Strong JVM tuning and performance optimization skills

• Experience with observability and monitoring tools (Grafana, Prometheus, Splunk, Jaeger, OpenTelemetry, etc.)

• Cloud & DevOps experience, including networking (VPC), IAM, sizing, and cost optimization

• Solid understanding of Linux, networking, storage, load balancing, and Kubernetes CNI

• SQL knowledge is a strong plus

• Experience in financial institutions or payment systems is highly desirable

• Excellent English communication skills

  
  

Nice to Have

• Experience with Go or Rust

• Strong background in payments or large-scale financial systems

• Passion for mentoring, coaching, and technical leadership

  
  

Benefits

• Private medical care (Medicover)

• Sports card (Multisport or equivalent)

• Life insurance

• Long-term cooperation on a stable, enterprise-scale project

• Access to modern technologies and large-scale distributed systems

• Real influence on architecture and technical direction