Senior Backend Engineer - Commercial Systems and Intelligence

The Commercial Systems and Intelligence squad is a newly formed team building the infrastructure that powers how SumUp attributes merchant acquisition, calculates commissions, and understands the full lifecycle of every merchant. You'll join at the very beginning, helping to shape how the squad works, the architecture it builds on, and the standards it holds itself to.

What you'll do

• Aggregating data from across the SumUp ecosystem to determine which acquisition channel or sales agent drove a merchant to take a valuable action
• Establishing data models, API contracts, and rule definitions that automate existing manual commission workflows for field and tele-sales agents, partnerships and merchant referrals
• Build the Lifecycle Event Log in close collaboration with the Merchant Intelligence squad. A centralized store of curated merchant lifecycle events used across attribution, recommendations, customer support and sales
• Build internal backoffices and APIs for sales representatives and leaders to monitor commission and modify commission plans, manage portfolios and resolve disputes
• Define and document API contracts, schemas, and integration patterns that other engineering teams can adopt confidently
• Establish best practices for testing, observability, and incident response within a newly formed squad
• Use AI and agentic coding tools deliberately, to scaffold services, write tests, explore unfamiliar code, and draft documentation while maintaining full accountability for what gets shipped

What you'll need

• Strong backend engineering background in Go, or typed-language generalist ready to ramp up quickly
• Experience designing APIs and distributed systems with clear contracts, versioning, and integration patterns
• Fluency in relational and analytical databases (PostgreSQL, Snowflake) and comfortable making the right choice for the right use case
• Experience building Kafka-based, event-driven systems and understanding event sourcing and CDC patterns
• Experience in auditable, high-trust systems where every decision must be traceable — fintech, payments, or similar domains
• Experience building services from scratch in greenfield, early-stage squads with limited prior context
• Expertise with testing, observability, and incident response practices as first-class concerns
• Ability to bridge technical and non-technical audiences and mentor others around you

What they offer

• Work with SumUp globally on large-scale fintech products from Berlin office
• Annual L&D budget of €2,000 for conferences and career advancement
• Equity stake through VSOP program
• Corporate pension scheme with up to 20% matching contributions
• 30 days sabbatical after 3 years of employment
• Benefits including Urban Sports Club subsidy, Kita placement assistance, subsidised office lunches