SumUp builds simple, affordable financial tools that help over 4 million small businesses across 37 markets get paid, manage their money, and grow. Beyond card payments, we offer a full suite of financial products - business banking, lending, invoicing, and money transfers - giving merchants everything they need in one place. We're a global fintech with over 3,000 people across 20+ offices, and Sofia has been one of our most important engineering hubs since the very beginning.
Our Transfers Excellence squad sits within SumUp's Global Bank, and owns the core services that power how merchants and consumers move money. E.g. IBAN-based transfers, money in and out, and peer-to-peer payments via the SumUp consumer app. With the high volume transfers per hour across our European markets. That means reliability isn't a nice-to-have - it's the baseline for us. Right now, the team is replacing a set of market-specific implementations with a single, unified global transfer platform that will serve Europe, the UK, Brazil, Chile, and eventually the US and Canada.
Join our team and contribute directly to platform-level architecture that will shape how SumUp moves money at scale - work that directly impacts millions of small businesses every day.
Our tech stack includes Kotlin, Java, Go, a bit of Elixir, AWS, Kafka, PostgreSQL, and Kubernetes, supported by a strong observability toolchain with Prometheus, Grafana, and Honeycomb. We also actively use AI‑assisted development tools such as Cursor, GitHub Copilot, and others.
🎥 Get a feel for life in our Sofia office.
What you'll do- Build and maintain backend services that sit at the heart of SumUp's transfer infrastructure, taking end-to-end ownership from development through to observability, testing and production support
- Contribute to the migration from market-specific services toward a unified global transfer platform, working across a mix of active services and legacy systems being decomposed
- Raise well-scoped pull requests, conduct thorough code reviews, and help maintain high standards of code quality and test coverage across the team
- Participate in incident reviews and the on-call rotation, taking accountability for the reliability of the services you build
- Contribute to the technical roadmap by participating in architectural discussions and proposing solutions for complex, distributed systems challenges
- Apply AI tooling to accelerate your own engineering workflows and contribute to raising the team's overall AI literacy
- Solid experience as a Backend Software Engineer in modern languages (e.g. Kotlin, Go, Java, etc.). Kotlin is the team's primary language and we also work with Java, Golang, and Elixir.
- Solid understanding of distributed systems and event-driven architecture. Experience with async processing and messaging tools like Kafka (or similar).
- Experience working with microservice architectures, including Spring Boot and event-driven patterns, alongside solid knowledge of relational databases and API design
- Comfortable working in high-throughput, regulated environments where reliability matters. Defensive coding and attention to edge cases are part of the job
- Clear communicator in written and spoken English, with a collaborative approach to working across global teams
- Curious about the product impact, not just the code. Comfortable thinking about how backend decisions affect the end user experience.
- 🌍 Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our modern Sofia 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 SumUp's future success
- 📚 A dedicated annual L&D budget of €2000 and 10 paid days of educational leave which can be used to attend conferences and/or advance your career through further education
- 🏖 Generous time off: 25 days of paid leave, plus one extra day per year of service (up to 35), along with public holidays and special leave options
- 🏥 Peace of mind: additional health insurance and life insurance
- 💪 Stay active: on-site yoga and a co-sponsored Multisport card offering access to hundreds of sports facilities
- 🍽 Meal support: benefit from a tax-free food voucher program plus flexibility via our Re:Benefits platform
- 🚌 Easy commute: free shuttle buses connecting directly to Joliot-Curie metro station
- 🌴 Break4me: 1-month sabbatical after 3 years of service
- 🔗 Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team
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 them to thrive. Today, over 4 million businesses in 37 markets rely on SumUp 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 SumUppers 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.
SumUp is proud to be an Equal Employment Opportunity employer, actively seeking and embracing diversity in our workforce. We don't make hiring or employment decisions based on 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. Our commitment extends beyond recruitment to creating a safe and respectful workplace where harassment of any form is strictly prohibited. Discover more about our culture and opportunities on our careers website, and follow our journey on LinkedIn, Instagram, and TikTok.
Job Application Tip
We recognise that candidates feel they need to meet 100% of the job criteria in order to apply for a job. Please note that this is only a guide. If you don’t tick every box, it’s ok too because it means you have room to learn and develop your career at SumUp.
Skills Required
- Solid experience as a Backend Software Engineer using modern languages (Kotlin preferred, Java or Go)
- Strong understanding of distributed systems and event-driven architecture
- Experience with asynchronous processing and messaging systems such as Kafka
- Experience with microservice architectures and frameworks (including Spring Boot)
- Solid knowledge of relational databases and API design (PostgreSQL experience helpful)
- Experience working in high-throughput or regulated environments with strong reliability focus
- Willingness to participate in on-call rotation and incident reviews, and support production systems
- Clear written and spoken English and ability to collaborate across global teams
- Familiarity with observability and monitoring tools (Prometheus, Grafana, Honeycomb)
- Experience with cloud platforms and container orchestration (AWS, Kubernetes)
- Comfort using AI-assisted development tools (e.g., Copilot, Cursor)
- Product-minded approach; ability to reason about backend decisions' impact on users
SumUp Compensation & Benefits Highlights
The following summarizes recurring compensation and benefits themes identified from responses generated by popular LLMs to common candidate questions about SumUp and has not been reviewed or approved by SumUp.
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Leave & Time Off Breadth — Paid time off is positioned as a standout, including 22 vacation days that increase with tenure, public holidays, a quarterly Wellness Day, special leave, and a fully paid one‑month sabbatical after three years. This combination makes time-off benefits feel notably robust in the overall rewards package.
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Healthcare Strength — Health coverage is described as comprehensive, with medical plan options (including carriers such as Cigna and Kaiser) plus dental and vision. Company-paid life insurance and disability coverage are also part of the protection package in the U.S. materials.
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Retirement Support — Retirement benefits include a published 401(k) match formula that provides an employer match up to a stated cap. The clarity of the match structure supports straightforward evaluation during offer comparisons.
SumUp Insights
What We Do
SumUp believes that every business should have access to affordable, easy-to-use financial solutions, no matter their size. That’s why more than 3 million businesses worldwide rely on SumUp to run their business. What started out as one card reader has now turned into a range of payment hardware, banking solutions, marketing, and loyalty tools, invoicing, and so much more. From sales and marketing to product and engineering, our cross-functional US team works together to ensure that small business owners can be successful doing what they love.
Why Work With Us
SumUp USA is part of the global SumUp organization that stretches across multiple continents from Berlin to Sao Paulo. Our teams are multicultural, have a collaborative mindset and bold goals. Join our mission if you want to become part of the success story and help empower over 3 million merchants using SumUp already!
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