Senior AI Backend Engineer

About the role

We are seeking a skilled and passionate Senior Backend Engineer to help lay the foundations of SumUp Edge — an AI-powered co-pilot that transforms raw merchant data into proactive, real-time business insights. You'll architect the systems that connect our data platform, LLM orchestration layer, and merchant-facing APIs, directly shaping how millions of small businesses understand and grow their business.

What you'll do

• Architect, design, develop and deploy our AI solutions and systems in production environments, ensuring reliability, high performance and scalability
• Design and build the orchestrator service that coordinates AI components, data flows, and external services to deliver reliable, real-time insights to merchants
• Develop and maintain scalable ETL pipelines or MCPs that process and sync heterogeneous data (text, images, audio) from various sources into the AI system
• Build and optimise the LLM Gateway infrastructure, including authentication, rate limiting, load balancing, and vector database management for the RAG system
• Create robust, high-performance APIs capable of handling multimodal data structures and high-volume requests, ensuring low-latency and production-grade reliability
• Implement observability tooling — including telemetry, logging, and tracing — to support auditing, evaluation, and continuous improvement of AI interactions
• Mentor backend engineers on the team, contributing to engineering standards, code reviews, and a culture of technical excellence
• Collaborate and communicate closely with data scientists, product managers, developers and other business stakeholders to bring state-of-the-art AI solutions to Customer Support

What you'll need

• Bachelor's or master's degree in Computer Science, Engineering, or a related field
• +6 years of experience developing software products (if they are ML or AI related is a plus)
• Advanced proficiency in Python, with hands-on experience building and scaling backend systems in production environments using tools like Kubernetes, Docker, Airflow, and Spark
• Strong knowledge of cloud infrastructure (AWS, S3) and CI/CD practices, with a track record of shipping reliable, maintainable systems
• Experience designing APIs and working with distributed data systems and message brokers such as Kafka or RabbitMQ
• Comfort working at the intersection of backend engineering and AI — including familiarity with LLMs, GenAI tooling, and machine learning concepts
• Experience with status monitoring using cloud-native tools or 3rd party (e.g. Prometheus, Cloudwatch, ...) and LLM traceability
• Excellent communication and collaboration skills to work effectively in cross-functional teams

What they offer

• Virtual Stock Option programme: you will own a stake in SumUp's future success
• A dedicated annual L&D budget of €2000 for your individual development
• A corporate pension scheme where we match up to 20% of your contributions
• Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days
• Break4me: 1-month sabbatical after 3 years of service
• Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, and subsidised office lunches