Senior/Lead Data Engineer

DOU Polska; Województwo mazowieckie; On-site; PLN 260,000 - 360,000; Full time

Job summary

DOU Polska is seeking a senior Java backend engineer to build a high-throughput data platform that processes millions of events per minute for an international client base. You will develop production-grade Java services, streaming pipelines with Kafka and Flink, and scalable data models.

You will collaborate with architecture, product and DevOps, optimise queries on PostgreSQL/ClickHouse/Redis, and ensure observability, security and cost efficiency.

Qualifications

• 6+ years building production distributed systems.
• 5+ years in Java with concurrency and JVM tuning.
• 3+ years with Kafka in production.

Responsibilities

• Build production-grade Java services and high-throughput data-processing components
• Develop and optimize Kafka and Apache Flink streaming pipelines
• Integrate data from multiple products into a unified data model
• Implement employee, department, device, and RBAC functionality
• Build services and APIs using Java, TypeScript, gRPC and Protobuf
• Design and optimize persistence on PostgreSQL, ClickHouse and Redis
• Improve scalability, reliability, throughput, latency, observability and cost
• Diagnose bottlenecks across pipelines, services, and databases
• Develop TypeScript and React frontend capabilities when needed
• Collaborate with architecture, product and DevOps teams
• Use AI-assisted tools while maintaining correctness and security

Skills

Java

Kafka

Flink

PostgreSQL

Redis

gRPC

Protobuf

Kubernetes

Docker

Distributed systems

English

Tools

ClickHouse

CI/CD

TypeScript

React

Protobuf

Job description

Our Customer

Our customer develops a digital employee experience platform that monitors endpoint and virtual desktop performance for enterprise organizations. The platform handles millions of events per minute across an international customer base.

Our Customer

Our customer develops a digital employee experience platform that monitors endpoint and virtual desktop performance for enterprise organizations. The platform handles millions of events per minute across an international customer base.

Your Tasks

• Build production-grade Java services and high-throughput data-processing components
• Develop, optimize and maintain large-scale Kafka and Apache Flink streaming pipelines
• Integrate data from multiple products into a unified organizational data model
• Implement employee, department, device and RBAC-related functionality
• Build services and APIs using Java, TypeScript, gRPC and Protobuf
• Design and optimize persistence on PostgreSQL, ClickHouse and Redis, including schemas, indexes and data-access patterns
• Improve scalability, reliability, throughput, latency, observability and operational cost
• Diagnose production bottlenecks across distributed pipelines, services and databases
• Develop TypeScript and React frontend capabilities when needed
• Collaborate with architecture, product and DevOps teams
• Use AI-assisted and agentic development tools while maintaining correctness, security and code quality

Required Experience And Skills

• 6+ years of experience building and maintaining production distributed, high-throughput systems
• 5+ years of professional Java experience, including concurrency, memory management and JVM performance tuning
• 3+ years of hands-on production experience with Apache Kafka, including partitioning, consumer groups, schemas, delivery guarantees, fault tolerance and throughput tuning
• 2+ years of hands-on production experience with Apache Flink, including stateful processing, windowing, checkpointing, state management, backpressure and fault recovery
• Proven track record of personally building, scaling and operating systems processing millions of events per minute
• Deep understanding of time-series and large-scale analytical databases, including modeling, ingestion, query tuning and partitioning
• Hands-on experience with PostgreSQL or another relational database
• Strong command of Protobuf, including schema evolution and compatibility
• Working knowledge of gRPC and service-to-service communication
• Hands-on experience deploying, monitoring and troubleshooting distributed workloads on Kubernetes
• Hands-on experience with Docker and CI/CD pipelines
• Solid understanding of production observability and incident resolution
• Hands-on use of AI-assisted and agentic coding tools in production, including critical review of generated code
• Proven ability to deliver independently, make architectural tradeoffs and identify risks early
• Strong communication skills for explaining technical decisions and working with international teams
• English – Upper-Intermediate

Would Be a Plus

• Hands-on experience with ClickHouse
• Hands-on experience with Redis
• Hands-on experience with TypeScript and React