Senior Backend Engineer — Global Expansion & AI Tools

SumUp; Berlin (NH); On-site; USD 127,000 - 173,000; Full time

Benefits offered by this job

Equity option

L&D budget €2,000

Pension match up to 20%

28 days leave

Urban Sports Club

Break4me sabbatical

Referral bonus

Job summary

SumUp in Berlin is seeking a Senior Backend Engineer for the Global Expansion squad to own core backend services across markets.

You’ll design in Golang/Kotlin, mentor peers, and shape AI tooling integration to accelerate market launches while ensuring reliability and security in financial transactions.

Join an office-first team committed to diversity, ongoing learning, and building scalable fintech infrastructure used by merchants worldwide.

Qualifications

• Backend experience with scalable distributed systems.
• Experience with payment/fintech or transaction safety.
• Mentorship and ownership in cross-functional teams.

Responsibilities

• Design and build scalable backend services in Golang and Kotlin for onboarding, transactions, and reconciliation across markets.
• Lead technical investigations for new market launches and mentor engineers on the team.
• Configure and maintain AI coding assistants with team-specific rules, prompts and context.
• Build AI agents that automate repetitive development tasks like integration stubs and API spec updates.
• Keep documentation accurate and AI-accessible to reduce time answering how X works.

Skills

Golang

Kotlin

Java

Tools

Cursor

Copilot

Continue

Job description

SumUp in Berlin is seeking a Senior Backend Engineer for the Global Expansion squad to own core backend services across markets.

You’ll design in Golang/Kotlin, mentor peers, and shape AI tooling integration to accelerate market launches while ensuring reliability and security in financial transactions.

Join an office-first team committed to diversity, ongoing learning, and building scalable fintech infrastructure used by merchants worldwide.