SumUp enables businesses to get paid easily, process orders quickly, sell online instantly and manage their money more efficiently. We create the tools businesses need to make their business and their customer experience thrive!

As a member of the Global Bank tribe, you’ll play a key part in helping us build SumUp's own digital bank. You’ll be part of a global, autonomous, cross-functional team that takes an aspect of our product and perfect it from concept to execution. Becoming a part of the Global Bank Tribe means working alongside ~250 people with 32 nationalities across Cologne, Berlin, São Paulo, Santiago, Sofia and Vilnius who love to take ownership, work with purpose and help businesses thrive.

As a Senior Android Developer, you'll be part of an experience team that is responsible for building reliable, secure and easy-to-use features inside our mobile app that’s exposed to millions of users across the globe. You’ll empower merchants with a smooth, effortless and engaging banking experience.

What you’ll do

• Design, build, and maintain the mobile banking features to empower our global merchant userbase with smooth and engaging banking operations.
• Work with large scale, highly available and resilient modern systems.
• Write high-quality, clean, and scalable code that meets the highest standards of performance and reliability.
• Participate in architectural discussions, propose solutions, and contribute to the technical roadmap of our Android application.
• Work closely with designers and product owners to build features that are maintainable, usable and beautiful.
• Help us rethink problems we've solved before in a different way as needs evolve and encourage and support continuous learning across the chapter.
• Develop a wealth of knowledge about our complex problem domain as well as its implications in the interface and the backend – and how to manage it in a clean way.

You’ll be great for this role if

• You have native development experience in Kotlin and are experience in building and shipping scalable complex Android applications.
• You have a solid understanding of software design patterns (e.g., MVVM, MVP) and expertise in building modular, scalable app architectures.
• You strive for clean code and know how to write flexible tests that won't break.
• You have expertise with testing frameworks and know how to implement robust test strategies (unit, snapshot, XCUITest, etc.).
• Care deeply about usability, quality, and building seamless user experiences.
• You have a product-focused mindset, enjoy collaborating with cross-functional teams, and take ownership of your work.
• You thrive in a team where you can learn and try new tech, collaborate on technical challenges and grow as a team.

The Tech We Work With

• Language: Kotlin, some legacy code is still maintained in Java
• UI: Jetpack compose - our development features are primarily using XML based designs and you are free to choose compose/xml
• Architectural Patterns: Clean architecture. Navigation controller and single activity arch. MVVM at presentation layer.
• Dependency Injection: Hilt
• Communication: Kotlin Flows and coroutines
• Detekt and checkstyle for code quality check
• Backend Integration: Majority of our tribe integrations are gRPC. 
• Our new features are done using REST - (Retrofit, Okhttp, moshi standard stack)
• Authentication: OAuth
• Firebase: For Analytics, remote config and crashlytics. Grafana for better observability and crash alert integration to slack 
• Testing: JUnit, Mockito and jacoco for reports. UI Testing: We have UI tests for critical flows but we go with pyramid structure where the unit tests are the base and UI tests are at the tip.
• VersionControl: Git and github 

Why you’ll enjoy working at SumUp:

• We’re a truly global team of 3200+ people from 80+ countries, spread across 4 continents
• The opportunity to work on large scale fintech products used by millions of businesses around the world
• Be part of a company and team that values diversity and celebrates unique perspectives - a global team of skilled professionals in an environment that fosters collaboration, learning, and growth.
• You’ll receive 25 days’ paid leave, plus 1 additional day for each year of employment.
• You can take up to 10 days’ educational leave to expand your skill set.
• Career growth and learning opportunities: We invest in your development through regular training, mentorship programs, SumUp University leadership cohort and a yearly learning budget (2,000 EUR)
• Enrollment onto our virtual stock ownership program - you will own a stake in SumUp’s future success
• Access to the SumUp Sabbatical, our Employee assistance program for mental health
• We offer additional health insurance, a subsidized Multisport card, free shuttle buses from Joliot-Curie metro station and other great benefits.
• You’ll attend global offsites and/or hackathons
• Join a global team where you belong: Check out our D&I Initiatives and Employee Resource Groups such as Pride Club, SumAfro, Neurodiversity, Grupos Mais, Women in Tech, and more

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 36 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.

Explore career opportunities with us and join a team driven by collaboration, innovation, and a shared vision of creating a world where everyone can build a thriving business. Discover more about our vibrant and inclusive work culture and how we work on our careers website, and follow our journey on LinkedIn and Instagram.