Senior Backend Engineer - Run & Grow

Academic Key; Köln; Hybrid; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Hack Days

Hack Weeks

Diversity & Inclusion

L&D budget €2,000

VSOP program

Pension scheme 20%

30 days sabbatical

Referral bonus

Urban Sports Club subsidy

Kita placement assistance

Relocation assistance

Subsidised office lunches

Job summary

SumUp is seeking a Senior Backend Engineer for the Run & Grow tribe in Cologne. You will design, build, and operate production-grade backend services and APIs primarily in Go, driving event-driven architectures and reliable data flows.

You’ll define contracts and data models, collaborate across teams, and mentor engineers to deliver scalable fintech products. You will work on merchant acquisition, identity, marketing tech, risk, and compliance with a focus on reliability, observability, and

Qualifications

• Strong backend engineering background in Go or similar typed language
• Experience designing APIs and distributed systems with clear contracts
• Fluent in relational databases like PostgreSQL; Snowflake experience is a plus
• Experience with testing, observability, incident response, and reliability practices
• Ability to mentor engineers and communicate complex trade-offs clearly

Responsibilities

• Design, build, and operate production-grade backend services and APIs in Go
• Develop event-driven workflows using Kafka and asynchronous processing
• Define service boundaries, data models, and API contracts for cross-team use
• Own technical work end-to-end from discovery to production follow-up
• Improve reliability via observability, security, and incident response

Skills

Go

APIs & microservices

Distributed systems

Mentoring

Observability

Tools

Kafka

PostgreSQL

Snowflake

REST APIs

Job description

Senior Backend Engineer - Run & Grow

SumUp · Cologne, North Rhine-Westphalia, Germany

Abroad Cologne, North Rhine-Westphalia, Germany Link validated

About the Run & Grow: Run & Grow is where SumUp builds the platforms and capabilities that help merchants discover, join, use, and continue growing with our products. The tribe brings together engineering, product, design, and revenue operations teams around two connected goals: helping SumUp serve and retain merchants, and accelerating acquisition, activation, and engagement. Our work sits at the heart of SumUp's growth engine. We turn complex challenges across merchant acquisition, identity, marketing technology, commercial systems, operations, risk, and compliance into reliable products and services that other teams can build on. The systems we create help SumUp move faster, make better decisions, and deliver a simpler experience to millions of small businesses. Joining Run & Grow means working on high‑impact engineering problems with a broad view of the business. You'll collaborate across disciplines and teams, shape the foundations behind important merchant journeys, and help create a more connected, scalable way for SumUp to run and grow.

What you'll do

Design, build, and operate production‑grade backend services, APIs, and integrations, primarily using Go. Build event‑driven workflows and distributed systems using technologies such as Kafka and asynchronous processing. Define clear service boundaries, data models, schemas, and API contracts that other teams can use confidently. Build capabilities supporting merchant acquisition, identity, marketing technology, operations, risk, and compliance. Own technical work end to end, from discovery and system design through implementation, testing, deployment, and production follow‑up. Modernise existing services and improve reliability through observability, security, failure handling, and incident response. Collaborate with Product, Data, Operations, Compliance, Risk, Sales, Marketing, and other engineering teams to turn complex requirements into practical solutions. Review code and designs, make pragmatic technical trade–offs, share knowledge, and mentor engineers around you.

You'll be great for this role if you

Bring a strong backend engineering background in Go, or are a typed‑language generalist ready to ramp up quickly. Have designed APIs and distributed systems with clear contracts, versioning, and integration patterns. Are fluent in relational and analytical databases (PostgreSQL, Snowflake) and comfortable making the right choice for the right use case. Have built Kafka‑based, event‑driven systems and understand event sourcing and CDC patterns. Have experience in auditable, high‑trust systems where every decision must be traceable fintech, payments, or similar domains. Have experience with testing, observability, and incident response practices and treat them as first‑class concerns, not afterthoughts. Take ownership of ambiguous problems and turn them into clear, scalable, and maintainable solutions. Communicate clearly, collaborate effectively, and explain technical concepts and trade‑offs to different audiences. Value pragmatic engineering, continuous improvement, mentoring, and reliable production operations.

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.
• 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 SumUp's future success.
• A corporate pension scheme where we match up to 20% of your contributions.
• 30 Days Sabbatical: Enjoy the unique opportunity to take a well‑deserved break with our 30 days sabbatical benefit after completing 3 years of employment with SumUp.
• Referral Bonus: Earn additional rewards by referring talented individuals to join the SumUp team.
• Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, relocation assistance, subsidised office lunches.

SumUp is an Equal Employment Opportunity employer that proudly pursues and hires a diverse workforce. SumUp does not make hiring or employment decisions on the basis of 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. SumUp also strives for a healthy and safe workplace and strictly prohibits harassment of any kind.

About us: 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