Senior Backend Engineer - MarTech in Berlin

About the team

The Mar Tech team builds the marketing and growth systems that help Sum Up reach more merchants around the world.

We combine backend engineering, data engineering, data science and external marketing platforms to create reliable, scalable solutions that improve conversion, increase operational efficiency and unlock new acquisition channels.

Our work spans recommendation engines, promotion management, affiliate and referral platforms, campaign feed publishing, creative automation, localization and conversion tracking integrations that send signals to advertising platforms.

We validate early ideas and prototypes into production-grade products that marketing teams can use independently, reducing manual work and helping campaigns reach customers faster.

You will join a diverse and distributed team that works closely with stakeholders across Acquisition Engineering squads, Online Marketing, Content & Localization, Engagement and Platform Infrastructure.

Because our systems sit at the intersection of technology, data and business growth, you will work on meaningful problems with multiple technical dependencies and a visible impact on Sum Up's acquisition strategy.

What you'll do

• Design, build and operate reliable backend services that support marketing and growth initiatives.
• Own features and engineering projects from discovery and technical design through delivery and production support.
• Build integrations with internal and external platforms, ensuring reliable data flows and maintainable interfaces.
• Define and evolve architectures for distributed services and event-driven systems.
• Improve the reliability, quality and operational excellence of existing services.
• Collaborate with technical and non-technical stakeholders to clarify requirements, communicate trade-offs and shape priorities.
• Contribute to a high standard of engineering through testing, code reviews, documentation and pragmatic technical decisions.
• Support the growth of the team by pairing with peers, sharing knowledge and mentoring less experienced engineers.

You’ll be great for this role if you have

• 5+ years of professional backend engineering experience. Strong experience with Go and the wider Go ecosystem.
• Hands‑on experience with distributed systems, microservices and event‑driven architectures.
• Experience with event‑streaming platforms and messaging brokers such as Kafka.
• Practical experience with Dev Ops practices and CI/CD tools, for example Git Hub Actions or Argo CD.
• Experience building new systems while also maintaining and improving legacy services.
• A strong understanding of software architecture, service boundaries, APIs, data flows, testing and production operations.
• Excellent written and verbal communication skills, with the ability to explain technical concepts and trade-offs to both technical and non-technical stakeholders.
• Proven stakeholder‑management skills and a collaborative approach to problem-solving.
• A strong sense of ownership and a commitment to writing clear, maintainable and testable code.
• Curiosity and enthusiasm for solving meaningful problems for users and the business.

Nice to have

• Experience in marketing technology, growth, acquisition or advertising platforms.
• Familiarity with React, Type Script, or Python.
• Experience in fintech or a related industry.
• 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 budget of €2,000 for attending conferences and/or advancing your career through further education
• Enrolment onto our VSOP program: You will own a stake in Sum Up's future success
• A corporate pension scheme where we match up to 20% of your contributions