KeyStep

Software Engineer (Golang) - Online Payments

SumUp
Sofia, Bulgaria
7 days ago
full-time

Skills & Technologies

GolangBackendAPIKafkaMicroservicesMicroservices ArchitectureHigh AvailabilityScalabilitySOLIDPostgreSQLAWSImplementationMakeDocumentationInfluencing

Job Description

At SumUp, we empower millions of small businesses worldwide. Our Payments Tribe is at the heart of this mission, processing billions of transactions across 36+ countries each year. We're building reliable, secure, and scalable systems that truly make a difference.

THE TEAM

Our robust payments processing platform has powered SumUp’s global business for over a decade. The Online Payments team, now a key part of our Payments Tribe, is responsible for facilitating all Card Not Present (CNP) transactions, ensuring our merchants can accept payments seamlessly online. This entire ecosystem is developed in Sofia by autonomous, cross-functional, and co-located squads, each owning their part of the platform end-to-end.

We are currently in an exciting phase of scaling and improving existing products, while also developing innovative new ones. You'll make a significant impact by improving and co-creating our existing and new microservices architecture platforms, tackling complex scaling and new development challenges. Scalability and high availability are always at the forefront of our work.

You'll join a team that values solid engineering and impactful solutions. You'll contribute to the design and development of our Golang-based Online Payments platform, working with cutting-edge tech and directly influencing our product.

OUR TECH STACK

We believe in using the best technology for each challenge, fostering an environment of continuous learning and exploration. Our current ecosystem includes Golang, Kafka Streams, PostgreSQL/RDBMS, AWS, microservices architecture.

WHAT YOU'LL DO

Co-design and develop high-performance, secure backend services for our Online Payments Platform

Participate in API design and implementation for both internal and external integrations.

Deliver business value through backend decisions and active participation in product discussions.

Ensure high code quality, comprehensive test coverage, and clear documentation.

Optimize application pe

Company & Role Analysis

JobSeeker+
Likely perks
Private MedicalPension25+ Days HolidayStock OptionsLearning BudgetFlexible Hours
Culture & working style

Neutral 2–4 sentence summary of what working at this company is like, drawn from public reviews and press coverage. Tone, collaboration style, pace, benefits highlights.

Market salary range

£45,000 – £60,000 (Glassdoor, Levels.fyi, 2025)

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