Java Lead with Kotlin, N-iX, RO

We are seeking an experienced Java Lead with a strong Java and distributed systems background to lead our cross-functional team based in Poland. This role combines deep technical expertise with people leadership responsibilities across backend and mobile engineering.
Our client, headquartered in California, is a global e-commerce leader connecting millions of buyers and sellers in over 190 markets. You will lead a team delivering cutting-edge AI/ML-powered experiences that transform the way people shop and sell online.

Your Role:
As an Java Lead, you will be responsible for the technical direction, people development, and delivery execution of a high-performing team. You will collaborate closely with product, AI/ML, and platform teams to design and deliver scalable features, ensuring operational excellence, clean architecture, and reliable services.

Key Responsibilities

• Lead and mentor a cross-functional team of backend (Java/Kotlin) and mobile engineers (iOS/Android)
• Drive architecture and design decisions for large-scale, distributed systems
• Provide technical leadership in areas such as API contracts (FGQL, REST, WebSockets), service integration, and performance optimization
• Promote best practices in observability, including metrics, tracing, and alerting
• Organize and lead on-call rotations, ensuring effective incident response and root-cause analysis
• Partner with product and ML stakeholders to define scope, set priorities, and ensure delivery of impactful solutions
• Conduct regular code and design reviews, contributing hands-on when needed to guide complex implementations
• Foster a culture of ownership, technical excellence, and continuous improvement

Qualifications:

• 2+ years of experience as Tech Lead with direct team leadership responsibilities
• 7+ years of backend development experience with Java or Kotlin
• Deep expertise in designing scalable distributed systems and microservices architectures
• Strong understanding of API contract design and maintenance: FGQL, REST, WebSockets
• Solid experience with Spring Framework and related Java/Kotlin tooling
• Hands-on experience leading teams through operational responsibilities, including on-call rotations
• Proficiency in modern observability practices: logs, metrics, tracing, incident response
• Excellent English communication skills (C1 level or above)
• BSc or MSc in Computer Science, Engineering, or a related technical field.

Preferred Qualifications:

• Experience with Apache Kafka or other real-time streaming systems
• Knowledge of reactive programming (e.g., Project Reactor)
• Experience with Docker and Kubernetes in a production environment
• Exposure to AI/ML-based applications or infrastructure
• Experience in e-commerce or consumer-facing platforms operating at scale