Senior Android Engineer- Hardware

veryday devices into secure, reliable card readers, from Bluetooth-connected dongles to fully in-house Tap to Pay on Android. You'll join a team solving genuinely hard problems: keeping working across flaky Bluetooth connections, handling online and offline flows without losing a transaction. It's a chance to go deep on Android engineering in a space where reliability really matters, since every merchant depends on these readers to get paid. What you'll do Build and maintain Android applications for card readers, SDKs, and the SuperApp, covering both new features and improvements to existing systemsWork on Bluetooth Low Energy connections, online and offline payment flows, and Tap to Pay functionalityRefactor and modernise legacy code to improve reliability, performance, and maintainabilityContribute to testing practices, including unit and integration tests, to raise overall code qualityCollaborate with peers and stakeholders across the team to manage priorities and shape solutions to technical challenges You'll be great for this role if... Several years of professional Android development experience, with solid proficiency in both Java and KotlinStrong knowledge of clean architecture principles and hands-on experience maintaining Android SDKsExperience of writing unit and integration tests, and comfort refactoring legacy code without breaking existing functionalityFamiliarity with CI/CD pipelines, such as GitHub Actions, and an interest in improving build and release processesAbility to adapt to ambiguity and shifting priorities, with strong communication skills for working independently with stakeholders 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 🌈 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 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 , 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. 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.