kotlin backend developer

SumUp provides a point-of-sale solution that enables cafes, shops, bars, hair salons, and other businesses to manage product catalogs, inventory, business analytics, compliance, and loyalty tools. The company focuses on empowering small business owners through a suite of financial and operational tools.

• Develop and evolve high-performance backend services and APIs using Kotlin and Spring Boot;
• Design and maintain robust data schemas and event-driven integrations using Kafka;
• Write clean, well-tested, production-grade code and contribute to code reviews;
• Collaborate with mobile and product teams to ship end-to-end features;
• Engage in daily pair programming to solve concurrency challenges and maintain architectural standards;
• Manage the development lifecycle, including CI/CD pipelines and production service health;
• Use AI coding agents to automate tasks and increase shipping velocity;
• Refactor and migrate mission-critical domain logic to simplify sales and catalog experiences.

• 3+ Years of experience in backend engineering with the JVM stack (Kotlin and Spring Boot preferred);
• Solid understanding of software design patterns, data modeling, and system architecture principles;
• Experience with Kafka, Postgres, and AWS in a production environment at scale;
• Experience with or strong interest in distributed and fault-tolerant systems;
• Fluent in English for clear communication with stakeholders;
• Nice to have: Experience with Kubernetes and cloud-native observability tools, knowledge of different programming paradigms, familiarity with high-scale applications, desire to share knowledge.

• Virtual Stock Option programme;
• Annual L&D budget of €2000;
• Corporate pension scheme with up to 20% matching;
• 28 Days of paid leave plus public holidays and special leave days;
• Urban Sports Club subsidy;
• Kita placement assistance;
• Subsidised office lunches;
• Break4me: 1-month sabbatical after 3 years of service;
• Referral bonus.