Software Engineer

Stack

Responsibilities

• ▹Design and build scalable backend services in Golang and Kotlin, covering merchant onboarding, transaction processing, and reconciliation across multiple acquirers and markets
• ▹Lead technical investigations for new market launches and mentor engineers on the team
• ▹Configure and maintain AI coding assistants (Cursor, Copilot, Continue) with team-specific rules, framework conventions, and testing patterns
• ▹Build AI agents that automate repetitive development tasks, such as generating integration stubs, updating OpenAPI specs, and flagging idempotency violations
• ▹Keep documentation accurate and AI-accessible

Requirements

• ▹Strong proficiency in Golang (primary) or a JVM language such as Java or Kotlin, with experience building distributed, fault-tolerant backend systems
• ▹Experience configuring AI coding assistants at a team level — defining rules, prompts, and context packages for consistent, framework-compliant output
• ▹Solid understanding of idempotency, retry policies, and transaction safety in payment or financial systems
• ▹Comfort working across multiple teams and domains simultaneously, navigating ambiguity and influencing without direct authority
• ▹A track record of taking ownership in complex, cross-functional environments

Soft skills

What we offer

• ▹Opportunity to work with SumUppers globally on large-scale fintech products from the Berlin office, office-first setup
• ▹Commitment to diversity and inclusion
• ▹Virtual Stock Option programme
• ▹Annual L&D budget of €2,000 for individual development
• ▹Corporate pension scheme with up to 20% matching
• ▹28 days of paid leave plus public holidays and special leave days
• ▹Urban Sports Club subsidy, Kita placement assistance, subsidised office lunches
• ▹Break4me: 1-month sabbatical after 3 years of service
• ▹Referral bonus

About the company

SumUp is a global fintech company empowering small businesses with simple and affordable payment solutions, with 3,000+ people from 93 nationalities across 22 offices on four continents.