Senior Backend Engineer - Golang

Senior Backend Engineer - Golang

You'll join Sum Up's Merchant Intelligence squad within the Engagement Mission — a newly formed team building foundational backend services that create a shared source of truth for product and merchant data across the business.

The team is focused on two core services:

• Product Catalogue Service — a global source of truth for all products Sum Up sells across every market, including hardware, subscriptions, and software, as well as market-specific feature and settings configuration.
• Merchant Intelligence Service — a centralized platform that aggregates merchant data from across the Sum Up ecosystem, helping teams understand the full merchant journey through product adoption, hardware sales, health signals, support interactions, and marketing cohorts.

By building these services, the squad is solving a company-wide challenge: product and merchant data is currently fragmented across multiple systems and teams, creating duplication, inconsistency, and reliance on manual workarounds. The Merchant Intelligence squad is building the platform foundations that will help teams across Sum Up move faster and make better decisions with reliable, centralized data.

As a Senior Backend Engineer, you'll help design and build these services from the ground up. You'll work closely with product, data, and engineering teams across Sum Up to create scalable systems that are reliable, easy to integrate with, and valuable to a broad range of internal users.

What you'll do:

• Design, build, and evolve foundational backend services that create a shared source of truth for product and merchant data across Sum Up, with a strong focus on scalability, reliability, and ease of adoption by internal teams
• Develop and maintain robust APIs, data models, and integration patterns that enable teams across the business to access consistent and trustworthy product and merchant information
• Build and improve data ingestion, aggregation, and event-processing pipelines that bring together signals from across the Sum Up ecosystem into actionable merchant intelligence
• Contribute to shaping the long-term architecture and strategy for the Product Catalogue and Merchant Intelligence services, helping establish platform capabilities that can be used across multiple systems and teams
• Write high-quality, maintainable backend code following engineering best practices for testing, observability, and production readiness
• Collaborate closely with product managers, data teams, and engineers across Sum Up to identify needs, solve complex data challenges, and turn them into effective technical solutions
• Work across squad and domain boundaries to support integrations, improve data consistency, and enable better internal tools, workflows, and merchant experiences
• Help define engineering standards, technical direction, and ways of working in a newly established squad operating in a complex and evolving domain

You'll be great for this role if you have:

• Strong professional experience in backend engineering, building and operating reliable production systems
• Solid experience with Golang and designing scalable backend services
• Strong knowledge of API design, system design, and data modeling
• Hands-on experience with Postgres or similar relational databases
• Experience with AWS, Docker, Kubernetes, and infrastructure-as-code tools such as Terraform
• Familiarity with event-driven architectures and message brokers such as RabbitMQ or Kafka
• A strong ownership mindset, with the ability to work independently and navigate ambiguity
• Clear communication skills and a collaborative approach to working across product, data, and engineering teams

Why you should join Sum Up:

Opportunity to work with Sum Uppers globally on large-scale fintech products used by millions of businesses worldwide, from our Berlin office. This involves an office-first setup

We take learning and experimentation seriously with Hack Days every second Friday, and entire global Hack Weeks.

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

A dedicated annual L&D…