Java Lead with Kotlin (#3849)

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

We offer*:

• Flexible working format - remote, office-based or flexible

• A competitive salary and good compensation package

• Personalized career growth

• Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)

• Active tech communities with regular knowledge sharing

• Education reimbursement

• Memorable anniversary presents

• Corporate events and team buildings

• Other location-specific benefits

*not applicable for freelancers