Senior Software Engineer (Golang)- Payments Experience

SumUp; Sofia (NM); On-site; USD 48,000 - 78,000; Full time

Benefits offered by this job

Office in Sofia

Virtual Stock Option programme

€2000 L&D budget

25 days paid leave + service bonus

Health and life insurance

On-site yoga

Job summary

SumUp Sofia is hiring a backend engineer to build and maintain Payments Experience services, focusing on payout settings and market-ready APIs. You will work in a small squad, shipping features and helping migrate legacy Ruby services while improving reliability.

The role requires Go expertise, RESTful APIs, PostgreSQL, Kubernetes, and AWS experience. You will collaborate across languages and contribute to scalable fintech platforms used by merchants.

Qualifications

• Strong hands-on experience building applications in Go.
• Comfortable working within microservices architectures and RESTful APIs.
• Good knowledge of SQL databases, particularly PostgreSQL.
• Familiarity with containerised deployments using Kubernetes and experience with AWS.
• Multi-language codebase experience (Go and Ruby).

Responsibilities

• Build and ship features within the Payments Experience domain, including payout instrument flexibility per market.
• Support ongoing maintenance and operational health of backend services.
• Contribute to decommissioning a legacy Ruby service and clean up dependencies.
• Help remove Platform DB dependencies from the Bank Accounts service as part of migration.
• Participate in planning and refinement sessions, sharing estimates.

Skills

Go

REST APIs

PostgreSQL

Kubernetes

AWS

Ruby

Microservices

Git

Tools

Docker

Job description

We believe in the everyday hero. Those who have the courage to follow their passion and who have the strength and determination to realise their dreams.

Small business owners are at the heart of all we do, so we're creating powerful, easy-to-use financial solutions to help them run their businesses. With a founder’s mentality and a 'team-first’ attitude, our diverse teams across Europe, South America and the United States work together to ensure that small business owners can be successful doing what they love.

About the team

The Payments Experience team sits at the heart of how millions of small businesses receive their money. We build and maintain the backend services that power payout settings, payout instruments, and the tooling that keeps payments flowing reliably across 37 markets. Right now, the tam is working through a meaningful technical challenge: migrating legacy services off an ageing platform database while continuing to deliver new capabilities for merchants and internal teams. This is a great opportunity to join a small, focused squad where your contributions are visible, your code matters, and there's real space to grow your craft in a complex fintech domain.

What you'll do:

• Build and ship features within the Payments Experience domain, including payout instrument flexibility per market and tooling to manage SUBA availability for sales teams
• Support the ongoing maintenance and operational health of the team's backend services, keeping them stable and reliable
• Contribute to decommissioning a legacy Ruby service that manages payout settings in the Dashboard and SuperApp, including cleaning up dependencies for a smooth transition
• Help remove Platform DB dependencies from the Bank Accounts service as part of a broader migration effort
• Take part in planning and refinement sessions, sharing technical assessments and effort estimates with the team

You'll be great for this role if you have:

• Strong hands‑on experience building applications in Go, with a solid grasp of core language concepts and the standard library.
• Comfortable working within microservices architectures and implementing or consuming RESTful APIs.
• Good knowledge of SQL databases, particularly PostgreSQL, and ability to write clean, efficient queries.
• Familiarity with containerised deployments using Kubernetes and experience working with AWS.
• Open to feedback, motivated to solve real engineering problems, and comfortable navigating multi-language codebases (the team works across Go and Ruby).

Why you should join SumUp:

• 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 in our Virtual Stock Option programme: you will own a stake in SumUp's future success
• A dedicated annual L&D budget of €2000 for your individual development, which you 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)
• Peace of mind: comprehensive health and life insurance - includes dental coverage
• 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 (100 EUR per month) plus flexibility via our Re:Benefits platform (40 EUR)
• Easy commute: free shuttle buses connecting directly to Joliot-Curie metro station
• Family-friendly: new baby bonus
• Break4me: 1-month sabbatical after 3 years of service
• Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team

About SumUp

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.