Senior Backend Engineer - Kotlin, Kafka, AWS + Spring Boot

Reply, Inc.; Katowice; Hybrid; PLN 145,000 - 246,000; Full time

Benefits offered by this job

Salary range 13k-22k PLN gross per月

Medical care

Language courses

Company events

Benefits platform

Multisport / gym cards

Cinema tickets

Job summary

OBI Smart Technologies is seeking a strong backend engineer to design and scale core systems powering product and assortment management within a large retail ecosystem. You will own backend architecture and system evolution in the assortment domain, building scalable services and integrations across an event-driven enterprise landscape.

Your responsibilities include designing scalable backend services, APIs, and integrations using Kotlin and Spring Boot, translating business requirements into

Qualifications

• Completed university degree in Computer Science or a comparable technical field.
• 6+ years of backend development experience with Kotlin and Spring Boot in complex environments.
• Strong expertise in REST APIs, microservices, distributed systems and event-driven architectures.
• Deep hands-on experience with Kafka and asynchronous processing in production.
• Strong experience with AWS and Kubernetes (including Amazon EKS).
• Solid PostgreSQL experience and data model design for performance and reliability.
• Experience with CI/CD, containerization, observability tooling and modern security concepts (OAuth2, IAM).
• Strong communication skills in English and Polish, with readiness to work in a hybrid model in Katowice.

Responsibilities

• Design and develop scalable backend services, APIs and integrations using Kotlin and Spring Boot within distributed systems.
• Translate business and product data requirements into robust, maintainable and scalable system designs.
• Lead the design and evolution of event-driven architectures and asynchronous processing using Kafka.
• Design and integrate backend systems within AWS and Kubernetes-based enterprise environments.
• Drive data modeling and persistence strategies using PostgreSQL and cloud-native approaches.
• Act as a technical interface between business, product and engineering teams, leading solution design and backlog refinement.
• Drive engineering best practices, observability, reliability and architectural consistency across the platform.
• Lead troubleshooting, optimization and continuous improvement initiatives while mentoring less experienced engineers.
• Cooperation within an internal community with networking events, coding challenges and company activities.

Skills

Kotlin

Spring Boot

REST APIs

Microservices

Distributed systems

Event-driven

Kafka

AWS

Kubernetes

PostgreSQL

CI/CD

Observability

Security concepts

English

Polish

Docker

Amazon EKS

Education

Computer Science degree

Tools

Docker

Amazon EKS

Job description

OBI Smart Technologies is seeking a strong backend engineer to design and scale core systems powering product and assortment management within a large retail ecosystem. You will own backend architecture and system evolution in the assortment domain, building scalable services and integrations across an event-driven enterprise landscape.

Your responsibilities include designing scalable backend services, APIs, and integrations using Kotlin and Spring Boot, translating business requirements into