Senior Backend Engineer

About the team

At Sum Up, we're on a mission to bring merchants and consumers closer together and help local communities thrive. Within the Consumer Mission, we're building a rewarding banking experience that connects people to the small businesses they love while tackling some of the most technically demanding challenges in fintech: critical infrastructure migrations, smooth, uninterrupted payment experiences, seamless open banking integrations, and high‑availability banking systems that can’t afford to fail – all while enabling free transactions for our merchants.

This role sits at the heart of that work — you’ll take real ownership of backend services that are close to our consumers, directly shaping their everyday experience, with impact that’s visible and felt across the entire platform.

• Build and maintain Backend services for Core neobanking features including bank transfers, open banking, savings accounts, and payment processing
• Take end-to-end ownership of features and projects, covering scoping, design, development, testing, deployment, and maintenance, leveraging Go along with Docker and Kubernetes for container orchestration.
• Take ownership of critical infrastructure migrations — including our banking core system transitions — without disrupting live customer experiences
• Collaborate closely with cross-functional teams including product, design, data science, security, and operations) to understand requirements, provide technical insights, and contribute to architecture discussions that ship meaningful banking features end-to-end
• Support fellow developers and actively help build a collaborative, innovative engineering culture
• Shape technical architecture and lead code reviews, helping define and promote best practices in code quality, testing, automation, and security to raise the overall engineering bar.
• Build and integrate tools and systems that improve operational efficiency and reliability, with strong observability through monitoring, alerting, and hands‑on involvement in incident response and post‑mortems.

• Strong proficiency in Go, Kotlin or Python, with a track record of building scalable, production-grade backend services
• Experience working with cloud platforms (AWS or comparable) and container orchestration tools such as Docker and Kubernetes
• Solid understanding of SQL and No
  
  SQL databases, distributed systems, and the trade-offs that come with high-availability requirements
• Comfort navigating complex, regulated environments — whether that's financial services, payments, or similarly high-stakes domains
• A collaborative, product-oriented mindset with the ability to work independently, communicate clearly, and adapt when priorities shift

Any of the following would be considered a plus

• Previous experience in a Growth-focused engineering team.
• Familiarity with the Fintech or Banking regulatory landscape.

No visa sponsorship available with this position

• Opportunity to work with a truly global, multicultural team from our central London Bridge location. 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
• Generous time off: enjoy 28 days of paid leave, plus bank holidays and special leaves
• A dedicated annual L&D budget for attending conferences and/or advancing your career through further education
• Health matters: private health insurance, including optical and dental
• Life made easier: salary-sacrifice commuter benefits via Gogeta
• Financial security: retirement scheme (Sum Up matches 7% when you contribute 5%)
• Peace of mind: life insurance from Met Life for 2× your salary
• 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…