Senior Software Engineer (Java, API)

Quick Facts

• Role: Senior Software Engineer (Java, API)

• Focus: Payment processing and API capabilities in future-state architecture

• Work location: Kraków (hybrid; ~6 days/month in office)

Description

You will design and deliver highly available, resilient payment processing and API capabilities as part of a future-state architecture. The role emphasizes high-quality engineering deliverables (with quality gates and robust tests), modernization toward cloud-based technology, and technical leadership across design, development, and problem resolution. You will collaborate closely with DevOps to enable automated infrastructure delivery and CI/CD with DevSecOps practices.

Responsibilities

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

• Produce high-quality code artifacts, surpass quality gates, and include robust test scripts

• Build and evolve highly available, resilient service capabilities

• Participate in the design and development of new capabilities

• Modernize the current payment estate with a focus on cloud-based technology adoption

• Lead by example and set expectations for software delivery quality

• Act as an expert: prevent problems, improve processes, and advise stakeholders

• Analyze and solve technical and business issues; provide technical solutions and guidance

• Resolve architectural or development blockers

• Partner with DevOps on automated infrastructure delivery and DevSecOps value streams

• Enable service deployment via CI/CD pipelines

• Conduct feasibility studies; prepare specifications and cost/benefit analyses for large systems

• Review new and existing systems to ensure operational integrity and stated objectives

• Design, code, test, debug, and document programs as required

• Provide architecture guidance aligned with best practices and global standards

• Ensure compliance with relevant controls and standards

Requirements

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

• Minimum 15 years of applied experience as an API engineer

• Strong API design skills and ability to create architectural artifacts (gap analysis, low-level designs, data models, etc.)

• 10+ years back-end microservices development, application security, and authentication development (plus cache/middleware experience)

• 10+ years programming experience in Java (ideally Go and Rust)

• Expertise in JVM tuning and diagnostic troubleshooting for performance optimization

• Expertise in distributed system design (microservices) and Spring Boot

• Expertise in Docker, Kubernetes, and service mesh

• Expertise in Kafka (build/configure clusters; produce and consume)

• Expertise in monitoring and observability tools (Splunk, Grafana, Prometheus, Jaeger, Kiali, OpenTelemetry)

• Cloud/DevOps expertise including VPC and firewall, IAM, and cloud delivery (sizing and costing)

• Knowledge of infrastructure: Linux OS, networking, storage, network load balancing, Kubernetes CNI

• Expert SQL coding ability is preferred

• Understanding of distributed databases

• Experience in financial services, ideally in payments

• Ability to work independently, think creatively, and take accountability

• Ability to lead, motivate, and develop team members (mentoring/coaching)

• Strong English communication skills (written and verbal)

Benefits

• Full-time employment contract; stable and long-term cooperation

• Well-defined career path in European engineering & IT consulting

• Opportunity to relocate and work across branches

• After project completion, opportunity to engage in subsequent projects

• Access to a dedicated Competences Manager

• Medicover medical and dental care, Medicover Benefits platform, Medicover Sport card

• Referral program; group life insurance; pension scheme

• Access to professional certifications with technology partners (e.g., Google, ISTQB)

• Access to relevant industry events and a Knowledge Sharing Program

Cooperation options also include B2B or Contract of mandate (UZ).