Senior Backend Engineer - Commercial Systems and Intelligence

As part of the Commercial Systems and Intelligence squad, you will help automate merchant attribution, commissions, and lifecycle analytics. You’ll shape data models, APIs, and event-driven infrastructure that power sales operations and leadership decisions. You’ll build systems that bring trust and visibility to attribution, lifecycle events, and commission workflows, starting from a greenfield setup. This role offers hands-on impact in a fintech environment with cross-functional collaboration and opportunities to influence architecture and standards.

• Hack Days every second Friday
• Global Hack Weeks
• L&D budget up to 2000 EUR/yr for conferences
• VSOP program (employee equity)
• Corporate pension scheme with up to 20% company match
• 30 days sabbatical after 3 years of service with SumUp? (explicitly stated as 30 Days Sabbatical)

• Aggregate data across SumUp to identify acquisition drivers (channel or agent) for valuable actions
• Define data models, API contracts, and rules to automate commission workflows for field and tele-sales, partnerships, and referrals
• Build the Lifecycle Event Log – a centralized store of curated merchant lifecycle events
• Develop internal back offices and APIs for sales to monitor commissions, manage portfolios, and resolve disputes
• Document API contracts, schemas, and integration patterns for cross-team adoption
• Establish testing, observability, and incident response practices within the squad
• Leverage AI and agentic coding tools to scaffold services, write tests, and draft documentation while maintaining accountability

• Strong backend engineering background in Go, or a typed-language generalist ready to ramp up
• Designed APIs and distributed systems with clear contracts and versioning
• Fluent in relational and analytical databases (PostgreSQL, Snowflake) and able to choose the right use case
• Built Kafka-based, event-driven systems and understand event sourcing and CDC patterns
• Experience in auditable, high-trust fintech or payments domains
• Experience starting services in greenfield, early-stage squads with limited context
• Testing, observability, and incident response practices treated as first-class concerns
• Resourceful, adaptable, end-to-end ownership mindset
• Ability to translate fuzzy problems for engineers and sales stakeholders and explain trade-offs
• Mentorship instincts to elevate peers and the team

• Communication across technical and non-technical audiences
• Mentorship and capability-building
• Adaptability and end-to-end ownership
• Go or typed-language proficiency
• API design and distributed systems
• PostgreSQL and Snowflake