Senior AI Backend Engineer

Team Description

SumUp Edge is our most ambitious product bet right now — an AI-powered co-pilot that transforms raw merchant data into proactive, real-time business insights. We're moving from being a payments processor to becoming an intelligent operating system for small businesses, and the backend infrastructure powering that shift needs to be world-class. This role sits at the very centre of that build: you'll architect the systems that connect our data platform, LLM orchestration layer, and merchant-facing APIs — and the work you do here will directly shape how millions of small businesses understand and grow their business.

We are seeking a skilled and passionate Senior Backend Engineer to help lay the foundations of this vision. In this role, you will design, architect, and develop infrastructure and systems that enables AI products to be successful, and that turn complex, real-world merchant data into scalable, production-grade information for AI solutions. Your expertise in backend and infrastructure combined with AI will be instrumental in shaping the intelligence layer and building sustainable infrastructure that powers our next generation of products.

You will collaborate closely with machine learning engineers, data scientists, product managers, and business stakeholders to translate business challenges into robust, high-impact AI capabilities. Your work will directly influence how small businesses operate, compete, and grow, positioning SumUp at the forefront of applied AI in fintech.

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, enhancing customer experience and improving operational efficiency.

You’ll be great for this position if you have

• 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.
• Ability to adapt to a fast-paced, dynamic work environment and quickly learn new technologies and techniques.
• Strong team player (m/f/d) with the ability to work with diverse groups of people in a productive and agile manner

Why you should join SumUp

• Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our Berlin office. This involves an office-first setup
• Commitment to Diversity and Inclusion: be part of a workplace that values and promotes diversity, fostering an inclusive environment where everyone's perspectives are respected and embraced
• Enrolment onto our 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, which you can use to attend conferences and/or advancing your career through further education
• 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
• Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, and subsidised office lunches
• Break4me: 1-month sabbatical after 3 years of service
• Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team

About SumUp

Be empowered to do more that matters. At SumUp, we're on a mission to empower small businesses across the globe by providing simple and affordable tools that allow them to thrive. Today, over 4 million businesses in 37 markets rely on SumUp as their financial partner to manage payments, finance and customer relationships.

Our commitment to small businesses is reflected in our diverse team of over 3,000 SumUppers from over 90 nationalities, united by global collaboration and an innovative mindset. Our core values lay the foundation for who we are and what we stand for, shaping our work culture and driving our success. We foster inclusivity and a continuous learning culture, providing a safe space for personal and professional growth. Our differences make us unique and strong as we strive to create an environment where everyone belongs and feels supported, no matter how they identify.

SumUp is proud to be an Equal Employment Opportunity employer, actively seeking and embracing diversity in our workforce. We don't make hiring or employment decisions based on race, colour, religion or religious belief, ethnic or national origin, nationality, sex, gender, gender identity, sexual orientation, disability, age or any other basis protected by applicable laws or prohibited by company policy. Our commitment extends beyond recruitment to creating a safe and respectful workplace where harassment of any form is strictly prohibited. Discover more about our culture and opportunities on our careers website, and follow our journey on LinkedIn, Instagram, and TikTok.

Job Application Tip

We recognise that candidates feel they need to meet 100% of the job criteria in order to apply for a job. Please note that this is only a guide. If you don’t tick every box, it’s ok too because it means you have room to learn and develop your career at SumUp.

Key skills/competency

• Backend Engineering
• AI/ML Infrastructure
• Python
• Kubernetes
• Docker
• Airflow
• Spark
• API Design
• Cloud Infrastructure (AWS)
• LLMs