Senior Java Developer (Kafka)

Quick Facts

• Role: Senior Java Developer (Kafka)

• Focus: scalable, asynchronous, high-performance systems with Kafka and event-driven architecture

Description

You will design and build scalable Java functionality without negatively impacting existing systems. The work centers on asynchronous processing and high-volume data processing using Kafka and event-driven architecture, together with SQL/NoSQL databases and CQRS. You will also verify AI-generated code using unit tests and edge cases.

Responsibilities

• Design and build scalable Java functionality while protecting existing systems

• Create solutions for asynchronous processing and high-volume data processing with Kafka

• Work with SQL and NoSQL databases and apply CQRS where appropriate

• Design with performance, isolation, maintainability, and security in mind

• Validate AI-assisted code via unit tests and edge-case coverage

Requirements

• Strong commercial experience with Java and Spring

• Very good knowledge of modern Java (Records, immutability, Stream API)

• Solid understanding of Java fundamentals: equals/hashCode, collections, reflection, Garbage Collection

• Good understanding of Spring internals and Dependency Injection

• Strong knowledge of SOLID, clean code, design patterns, and code smells

• Experience with Kafka and event-driven architecture

• Understanding of idempotency, at-least-once delivery, and Dead Letter Queues

• Experience designing scalable, asynchronous, high-performance systems

• Good understanding of SQL and NoSQL databases and ability to choose the right approach

• Knowledge of CQRS, ACID, indexing, and database partitioning

• Ability to discuss architectural decisions, explain trade-offs, and adapt solutions

• Practical experience with AI tools such as GitHub Copilot and ability to verify generated code

• Strong communication skills and collaborative approach to design

• Very good English and Polish

Benefits

• Private medical care

• Sports card

• Training courses

• 100% remote work (or another preferred system)

• International working environment and international projects

• Small team