Junior Backend Engineer (Golang) - Payments Tribe

At SumUp, we build the financial tools that empower small businesses around the world. Our Payments Tribe is at the heart of that mission - powering billions of transactions across 36+ markets every year. Our Sofia office is a key engineering hub and home to our Payments Processing Domain, where teams work on strategic, high-impact initiatives across in-person and online payment methods. The Role We're looking for a Junior Backend Engineer (Go) to join our Payments Processing team in Sofia. You'll work alongside senior and mid-level engineers on a strategic consolidation of payment processing capabilities - covering both in-person and online alternative payment methods. This is a structured, mentorship-driven role designed to set you up for long-term success. You'll work on real projects with meaningful impact - from card recognition improvements and smart transaction routing to PAR data solutions that power more accurate loyalty programmes. What You'll Do Build and maintain Go-based backend microservices as part of the Payments Processing domain Deliver on daily maintenance, compliance, and support tasks alongside more senior engineers Work with event-driven architectures using Kafka and consume/build RESTful APIs Participate in code reviews, improve observability, and contribute to engineering best practices Collaborate cross-functionally with Hardware, Online Payments, POS tribes and local market teams You'll Be Great for This Role If You Have experience or a strong interest in Go (Golang) - from work, studies, or personal projects Have any backend programming experience and understand core concepts like REST APIs, data structures, and concurrency Are familiar with SQL and/or NoSQL databases (we work with CockroachDB, PostgreSQL, and Kafka) Are eager to build a foundational understanding of system architecture, software design principles, and data modelling Are open to feedback, collaborative by nature, and not afraid to ask questions or pair with