Software Engineer - Global Expansion

Software Engineer - Global Expansion

The Global Expansion Acquiring Squad is the engine behind Sum Up's growth into new markets — integrating local payment acquirers, enabling merchant onboarding, and ensuring transactions flow reliably across countries like Mexico, Canada, New Zealand, and Australia. This role sits at the heart of that mission, owning critical backend systems while also shaping how the squad works — building AI agents and developer tooling that make the entire team faster and smarter.

If you're a backend engineer who wants real ownership, enjoys working in ambiguous and complex environments, and is genuinely excited about teaching AI how your codebase works (not just using it for autocomplete), this role is for you.

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 — so generated code fits our systems, not generic templates

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, so the team spends less time answering "how does X work?" and more time shipping

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 that produce 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 where the scope isn't always clearly defined

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

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

Enrolment onto our Virtual Stock Option programme: you will own a stake in Sum Up's future success

A dedicated annual L&D budget of €2,000 for your individual development, which can be used to attend conferences and/or advance your career through further education

A corporate pension scheme where we match up to 20% of your contributions

Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days

Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, subsidised office lunches

Break4me: 1-month sabbatical after 3 years of service

Referral Bonus: earn additional rewards by referring talented individuals to join the Sum Up team

Be empowered to do more that matters.

At Sum Up, we're on a mission to empower small businesses across the globe by providing simple and affordable tools that allow them to thrive. Today, over 4 million businesses in 37 markets rely on Sum Up as their financial partner to manage payments, finance and customer relationships.

Our commitment to small businesses is reflected in our diverse team of over 3,000 Sum Uppers from over 90 nationalities, united by global collaboration and an innovative mindset. Our core values lay the foundation for who we are and what we stand for, shaping our work culture and driving our success. We foster inclusivity and a continuous learning culture, providing a safe space for personal and professional growth.

Our differences make us unique and strong as we strive to create an environment where everyone belongs and feels supported, no matter how they identify.

Sum Up is proud to be an Equal Employment Opportunity employer,…