Software Engineer (Golang) - Online Payments

At SumUp, we empower millions of small businesses worldwide. Our Payments Tribe is at the heart of this mission, processing billions of transactions across 36+ countries each year. We're building reliable, secure, and scalable systems that truly make a difference. THE TEAM: Our robust payments processing platform has powered SumUp’s global business for over a decade. The Online Payments team, now a key part of our Payments Tribe, is responsible for facilitating all Card Not Present (CNP) transactions, ensuring our merchants can accept payments seamlessly online. This entire ecosystem is developed in Sofia by autonomous, cross-functional, and co-located squads, each owning their part of the platform end-to-end. We are currently in an exciting phase of scaling and improving existing products, while also developing innovative new ones. You'll make a significant impact by improving and co-creating our existing and new microservices architecture platforms, tackling complex scaling and new development challenges. Scalability and high availability are always at the forefront of our work. You'll join a team that values solid engineering and impactful solutions. You'll contribute to the design and development of our Golang-based Online Payments platform, working with cutting-edge tech and directly influencing our product. OUR TECH STACK: We believe in using the best technology for each challenge, fostering an environment of continuous learning and exploration. Our current ecosystem includes Golang, Kafka Streams, PostgreSQL/RDBMS, AWS, microservices architecture. WHAT YOU'LL DO: Co-design and develop high-performance, secure backend services for our Online Payments Platform Participate in API design and implementation for both internal and external integrations. Deliver business value through backend decisions and active participation in product discussions. Ensure high code quality, comprehensive test coverage, and clear documentation. Optimize application pe