Senior Fullstack Engineer - Localization
- Level
- Senior
Not stated in the posting: salary, work type, visa.
Open. First seen 3 October 2026.
About the role
The Localization team builds and owns the systems that make sure every merchant, in every one of our 38 markets, can understand and use our products in their own language. It's one of the most critical enablers of SumUp's global growth, sitting at the heart of how fast and how well we can go to market anywhere in the world.
As our Senior Full Stack Engineer, you'll bring dedicated engineering ownership by working closely with the team to scope, build and ship the systems, integrations and tooling accelerate the ongoing evolution of our localization platform towards greater automation, scalability and end-to-end integration. If you want autonomy, meaningful scope, and the chance to shape a growing function, this is the role.
What you'll do:
- Design, build and optimise localization solutions across product, CMS, CRM, marketing and design systems, so content moves faster without compromising quality
- Improve the localization management platform to give the team greater visibility and control while reducing manual steps
- Embed automated language and quality checks into several steps of the localization workflows, catching issues before they reach production
- Improve the experience for developers, designers, marketers and content teams by ensuring localization solutions support their processes and ways of working
- Partner with Web and Mobile, Website, Comms Platform and other technical teams to enable localization capabilities across the technology stack
- Explore how AI and language technology can strengthen and future-proof the localization stack, while ensuring solutions meet evolving compliance requirements.
You'll be great for this role if:
- Strong background in backend engineering, ideally with Go (alternatively knowledge with Python, Rust or C++)
- Experience building and maintaining RESTful APIs in a microservices or distributed systems environment
- Working knowledge of databases such as PostgreSQL and event streaming tools such as Kafka
- Comfort translating priorities from non technical stakeholders into scoped, shippable engineering work
- Ability to operate independently across a fragmented, distributed system landscape, working within architecture owned by other teams
- Exposure to frontend frameworks such as Reactjs and languages like Typescript
- Experience working with translation management systems (TMS), or with the localization of web or mobile applications and other content platforms.
Why you should join SumUp
🌎 Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our Berlin office. This involves an office-first setup
SumUp's standard text
🌈 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 for your individual development, which can be used to attend conferences and/or advance your career through further education
💶 A corporate pension scheme where we match up to 20% of your contributions
🏖 Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days
🎁 Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, subsidised office lunches
🌴 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
SumUp's standard text
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 38 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's standard text
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.
Berlin office
SumUp's standard text
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.
What this role asks for
Particular to this role
C++ · Microservices · Rust
Rare in SumUp's other 56 open postings.
Standard for full stack roles
PostgreSQL · Python · REST · React · TypeScript
Common in full stack postings at any company.
80% of this description is written for the role. The rest is SumUp's standard text, folded away below.
Read against SumUp's other open postings on this site.
The team: Engineering HIRES STEADILY
This role is one of 26 open in Engineering. 5 were posted in the last 30 days and the oldest in March: a team that hires all year rather than one being built.
WHAT THE TEAM WORKS WITH, ACROSS ITS POSTINGS
Kafka (14 of 26), Golang (13 of 26), Java (11 of 26), AWS (10 of 26), CI/CD (10 of 26), Kotlin (9 of 26), Kubernetes (8 of 26)
OTHER ROLES ON THIS TEAM
- Senior Backend Engineer - Cards posted Oct 9
- Backend Engineer - Run & Grow posted Oct 7
- Senior Backend Engineer - Run & Grow posted Sep 24
- Senior Backend Engineer - Run & Grow posted Sep 24
- Senior Backend Engineer (Golang) - Payments Infrastructure posted Sep 21
- Android Engineer posted Sep 15
- iOS Engineer posted Sep 15
- Senior Embedded Software Engineer- Hardware posted Sep 4
- Senior Backend Engineer - Identity Lifecycle posted Sep 1
- Senior Software Engineer (Lending Team) posted Sep 1
- Senior Software Engineer (Golang) – Pricing Domain posted Aug 26
- Backend Engineer - Merchant Risk Intelligence posted Aug 25
- Senior Backend Engineer - MarTech posted Aug 19
- Backend Engineer - Merchant Risk Intelligence posted Aug 10
- (Senior) Backend Engineer posted Aug 3
- Senior Platform Engineer posted Jul 29
- Engineering Manager posted Jul 7
- Fullstack Engineer - Bank posted Jun 17
- Senior Backend Engineer posted Jun 10
- Backend Engineer - Cards posted Jun 9
- (Senior/Mid) Software Engineer, Golang - Payments Platform posted Apr 23
- Engineering Manager - Verification posted Apr 15
- Engineering Manager - Verification posted Apr 15
- iOS Engineer - Design System posted Feb 18
- Backend Engineer- Global Bank posted Mar 6
From the team and dates on SumUp's own job board.
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