Senior Backend Engineer (Java, Kotlin, Spring Boot, AWS)

About the Position

We are looking for a strong backend engineer who wants to design and scale core systems powering product and assortment management across a large retail ecosystem.

You will take ownership of backend architecture and system evolution within the assortment management domain, building scalable services and integrations across a complex, event-driven enterprise landscape. You act as a technical driver within the team, working closely with architects, product owners, and stakeholders to deliver robust, high-quality solutions.

Responsibilities

• Design and develop scalable backend services, APIs, and integrations using Kotlin and Spring Boot within distributed systems.
• Translate complex 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.

Requirements

• Completed university degree in Computer Science or a comparable technical field.
• 6+ years of professional experience in backend development using 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 patterns in production systems.
• Strong experience with AWS and Kubernetes (including Amazon EKS) in scalable environments.
• Solid experience with PostgreSQL and designing performant, reliable data models.
• 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.

We Offer

• Motivizer Benefits Platform to choose and manage all your benefits in one place. You receive a budget (550 PLN monthly). You can choose medical care package, meal tickets, sports cards (we have Multisport and on preferential terms, we have membership cards to one of the most popular Gyms), cinema tickets, shop vouchers, discounts and many more.
• Language Courses – you'll have access to a multi-language learning platform enabling you to practice your language skills and learn new ones!
• Regular and systematic further training opportunities - both internally and from external providers. We support your ongoing learning and development.
• Cooperation within an internal community is our everyday reality. We have networking events, coding challenges, and company parties for different occasions.

About the Company

Reply Polska is made up of a network of highly specialized companies, which support leading industrial groups in defining and developing business models to optimize and integrate processes, applications, and devices, using new technology and communication paradigms, such as Artificial Intelligence; Big Data; Cloud Computing; Digital Communication; Internet of Things; Mobile and Social Networking.

Develop yourself and the digital future – at Reply!