At SumUp, we build the financial tools that empower small businesses around the world. Our Payments Tribe is at the heart of that mission - powering billions of transactions across 36+ markets every year. Our Sofia office is a key engineering hub and home to our Payments Processing Domain, where teams work on strategic, high-impact initiatives across in-person and online payment methods.
We're looking for a Junior Backend Engineer (Go) to join our Payments Processing team in Sofia. You'll work alongside senior and mid-level engineers on a strategic consolidation of payment processing capabilities - covering both in-person and online alternative payment methods.
This is a structured, mentorship-driven role designed to set you up for long-term success. You'll work on real projects with meaningful impact - from card recognition improvements and smart transaction routing to PAR data solutions that power more accurate loyalty programmes.
What You'll Do- Build and maintain Go-based backend microservices as part of the Payments Processing domain
- Deliver on daily maintenance, compliance, and support tasks alongside more senior engineers
- Work with event-driven architectures using Kafka and consume/build RESTful APIs
- Participate in code reviews, improve observability, and contribute to engineering best practices
- Collaborate cross-functionally with Hardware, Online Payments, POS tribes and local market teams
- Have experience or a strong interest in Go (Golang) - from work, studies, or personal projects
- Have any backend programming experience and understand core concepts like REST APIs, data structures, and concurrency
- Are familiar with SQL and/or NoSQL databases (we work with CockroachDB, PostgreSQL, and Kafka)
- Are eager to build a foundational understanding of system architecture, software design principles, and data modelling
- Are open to feedback, collaborative by nature, and not afraid to ask questions or pair with teammates
- Are motivated to solve engineering problems that deliver real business value
- Can handle and are excited to learn multiple tech stacks (Go and Java)
- Experience with AWS, Kubernetes, or Docker
- Exposure to Elixir or another functional programming language
- Background or interest in the fintech / payments industry
- Contributions to open-source Go projects
- Work at a global fintech company with real impact on millions of merchants worldwide
- Mentorship-first culture — you'll work closely with senior and mid-level engineers from day one
- Modern tech stack: Go, Kafka, CockroachDB, PostgreSQL, AWS, Kubernetes
- Sofia office-based role in a collaborative, international environment
- Access a €2,000 annual L&D budget to attend conferences or advance your career through education.
- Enjoy 25 days of paid leave (increasing with tenure), plus paid vacations for special occasions and a 1-month sabbatical every 3 years.
- Benefit from extra perks like health and life insurance, co-sponsored Multisport cards, childbirth/adoption bonuses, discounts, a referral program, monthly food vouchers, flexible benefits, and more.
Please note: This role requires the right to work in Bulgaria. We are currently not able to support visa applications or relocation for this position at this time.
About us:
SumUp is a leading financial technology company, founded in 2012 with the goal of empowering small businesses around the globe. We’re the financial partner of choice for more than 4 million merchants in over 35 markets. We collectively build, plan and fine-tune the technology that drives SumUp and empowers small businesses around the world.
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 business. 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.
SumUp is an Equal Employment Opportunity employer that proudly pursues and hires a diverse workforce. SumUp does not make hiring or employment decisions on the basis of 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. SumUp also strives for a healthy and safe workplace and strictly prohibits harassment of any kind.
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.
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.
-
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.
-
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.
-
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
Similar Jobs
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!
Gallery
