Android Developer | Health & Fitness Startup

Senior Android Engineer - KMP

Sumup

Salary range: 18 850 - 29 660 PLN per month About the team SumUp’s Point-of-Sale (POS) solution empowers cafes, shops, bars, hair salons, and other businesses to operate efficiently and grow. It offers a wide range of features, including product catalogs, inventory management, business analytics, compliance support, and loyalty tools. Our POS solution integrates seamlessly into the SumUp SuperApp, which supports both our proprietary register hardware and mobile devices like tablets and phones. As a Senior Android Developer, you’ll collaborate with a dynamic, cross-functional team of Product Managers, Product Designers, Engineering Managers, and fellow engineers. About the role We’re evolving toward a Kotlin Multiplatform (KMP) strategy, enabling shared development across Android and iOS. In this role, you’ll learn, refine, and help implement this technology, shaping the future of our mobile apps. You’re a developer who values user-centric design, precision, and seamless collaboration. You bring structure to communication and thrive in a cross-functional environment.  This role will be a B2B based role in Warsaw. What you’ll do * Build new features for the item catalog within the SumUp SuperApp * Help improve the architecture of the application and contribute to our Kotlin Multiplatform strategy * Enhance and maintain our unified android app, distributed across 60+ countries, ensuring high-quality, scalable solutions * Shape the product’s evolution by identifying opportunities for improvement and contributing to daily decision-making * Write thorough documentation and implement robust testing for features before shipping * Collaborate closely with Designer, Product Manager and Android engineers to deliver a unified UX experience across platforms You’ll thrive in this role if: * You have 8+ years experience in mobile engineering with Android and Kotlin. * You have 2+ years of experience working with Jetpack Compose. * You have a solid understanding of software design patterns (e.g., MVVM, MVI) and expertise in building modular, scalable app architectures. * You have good knowledge of reactive programming (Flow, Coroutines and Concurrency). * You have a strong grasp of testing best practices: knowing what to test, why, and how to write resilient tests. * You strive for clean code, and you are flexible to balance pragmatism and perfection. * You have a keen interest in multi-platform development using Kotlin Multiplatform. WHY YOU SHOULD JOIN SUMUP (WARSAW) 🇵🇱 🌎 Opportunity to work , from our vibrant Warsaw office with inspiring art-filled lounges and a skyline terrace in the Mennica Legacy Tower.  🌈 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 VSOP program: you will own a stake in SumUp’s future success  🚴 Fitness support: work out on-site at our gym or explore the city using the Multisport Card, subsidised by SumUp for access to sports facilities across Warsaw  🩺 Commitment to well-being: access health insurance coverage for you and your family, plus life insurance to further protect your peace of mind  🏖️ Generous time off: enjoy 26 days of paid leave plus public holidays and special leave days 🌴 Break4me: 1-month sabbatical after 3 years of service  🔗 Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team *Disclaimer The stated salary range represents the expected compensation for candidates who meet the core requirements of this role. Offers above this range may be considered in exceptional circumstances, subject to internal review and approval, where a candidate's qualifications, skills, or experience significantly exceed the role's standard expectations.   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.

Senior Product Engineer, Cross-platform

Welltech

WHO ARE WE? Welltech is a global wellness technology company with Ukrainian roots. Our mission is to build and scale wellness apps globally through state-of-the-art, tech-driven performance marketing. We are one of the most established players in the wellness app space, and we are accelerating. Over 25.5 million people across the world use our apps — Muscle Booster, Yoga-Go, and WalkFit — to build healthier habits, move more, and feel better every day. Every subscription represents a real person making a real change in their life, and we take that seriously. With 500+ people across hubs in Cyprus, Ukraine, Poland, Spain, and the UK, we combine the scale of a market leader and the drive of a team that's just getting started. The Product Engineer Mindset We don’t hire people to implement specs. We hire people who can spot the right problem to solve, talk directly to product, design, data, and users to sharpen it, and ship the thinnest version that proves the bet, then iterate. If this is you, you probably: * Measure your work in outcomes, not output. A feature isn’t done when it merges; it’s done when the metric moves, or you’ve learned it won’t, and killed it. * Go to the source. You don’t wait for a perfect PRD. You sit with PMs, designers, marketers, and data, and sometimes users directly, to understand what’s actually being asked. * Own things end-to-end. From the first conversation about a problem through architecture, code, rollout, monitoring, and the follow-up experiment. You don’t hand work off at a boundary. * Have a strong bias to ship. Prototypes, A/B tests, feature flags, kill switches. You’d rather get something in front of users this week than a perfect plan in two months. * Treat AI as leverage, not a novelty. You use agentic workflows to compress the loop between idea and learning, for yourself and the team.   What You’ll Own This is an ownership role, not a feature factory seat. You’ll be on the hook for outcomes across the stack, not just the code in your area: * A cross-platform foundation, end to end. Mobile, web, BFF, and infrastructure layers, built and evolved with an AI-first, agentic development approach, and held to outcomes you helped define. * Scalable foundations for health & fitness apps. React Native and modern web technologies, designed so product teams can ship and experiment faster without rederiving the basics each time. * The discovery loop with stakeholders. Working directly with product, design, marketing, and data to translate business bets into running experiments, not just tickets in a backlog. * AI-agentic workflows across the SDLC. You’ll continuously improve how the team uses AI to raise productivity, code quality, and delivery speed, and prove the impact. * Shared platform capabilities. Internal tooling, CI/CD pipelines, and AI-assisted workflows that make every engineer at Welltech faster and the product better. * Native mobile and media experiences. Video playback, streaming, and HLS, owned from native integration through user-perceived quality. * Modular, reusable systems. Backend-driven UI, white-label capabilities, and the architectural choices that let one team’s work compound for the next. * Reliable integrations. Between frontend clients, BFF services, and platform infrastructure, with you on the hook for the health of the seams. * The engineering culture. Architecture discussions, code reviews or pairing when working on trunk based development workflows, documentation, and continuous improvement, leading by what you ship and how you ship it.   WHAT WE’RE LOOKING FOR Key responsibilities: * Build and evolve a cross-platform ecosystem covering mobile, web, BFF, and infrastructure layers using an AI-first, agentic development approach * Design scalable foundations for health & fitness applications powered by React Native and modern web technologies * Work directly with product, design, and marketing stakeholders to rapidly translate business needs into scalable technical solutions and experiments * Develop and continuously improve AI-agentic workflows across the full development lifecycle to increase team productivity, code quality, and delivery speed * Develop shared platform capabilities, internal tooling, CI/CD pipelines, and AI-assisted workflows that improve development speed and product quality * Work on native mobile integrations and advanced media experiences, including video playback, streaming, and HLS-based solutions * Contribute to modular architectures, reusable systems, backend-driven UI solutions, and white-label application capabilities * Build reliable and scalable integrations between frontend clients, BFF services, and platform infrastructure * Participate in architecture discussions, code reviews, documentation, and continuous improvement of engineering workflows   Required skills: * Strong commercial experience with React Native and modern TypeScript-based application development * Solid understanding of full-stack architecture including mobile, web, BFF, and cloud/infrastructure layers * Experience building scalable cross-platform systems and shared application foundations * Deep understanding of software architecture, modular systems, scalability, and performance optimization * Experience working with CI/CD pipelines, automation tooling, and modern developer workflows * Strong engineering mindset focused on maintainability, reliability, testability, and fast iteration * Comfortable working in AI-assisted or agentic development environments and adopting new AI-driven workflows quickly * Experience with backend-driven UI architectures   Nice to have: * Experience building white-label mobile applications or multi-brand ecosystems * Experience designing and implementing BFF (Backend for Frontend) services * Hands-on backend development experience with TypeScript (Node.js) * Experience building internal developer platforms, shared tooling, or scalable platform capabilities * Familiarity with OWASP mobile security best practices * Experience with engineering methodologies focused on rapid iteration and high developer productivity (Trunk Based Development, CI/CD mindset, TDD, BDD, XP, etc.) * Strong experience with native mobile integrations and media/video playback technologies * Hands-on experience with HLS streaming and native video player integrations on iOS and Android (AVPlayer, ExoPlayer, Chromecast, AirPlay)   Candidate journey: ⭕️ Recruiter call --> ⭕️ Meet a Hiring Manager--> ⭕️ Skills assessment-->Live coding   Check out some of our products Muscle Booster — https://musclebooster.fitness/ Yoga-Go — https://yoga-go.io/ WalkFit - http://walkfit.pro

Senior Fullstack Engineer, Cross-platform

Welltech

WHO ARE WE? Welltech is a global wellness technology company with Ukrainian roots. Our mission is to build and scale wellness apps globally through state-of-the-art, tech-driven performance marketing. We are one of the most established players in the wellness app space, and we are accelerating. Over 25.5 million people across the world use our apps — Muscle Booster, Yoga-Go, and WalkFit — to build healthier habits, move more, and feel better every day. Every subscription represents a real person making a real change in their life, and we take that seriously. With 500+ people across hubs in Cyprus, Ukraine, Poland, Spain, and the UK, we combine the scale of a market leader and the drive of a team that's just getting started. The Product Engineer Mindset We don’t hire people to implement specs. We hire people who can spot the right problem to solve, talk directly to product, design, data, and users to sharpen it, and ship the thinnest version that proves the bet, then iterate. If this is you, you probably: * Measure your work in outcomes, not output. A feature isn’t done when it merges; it’s done when the metric moves, or you’ve learned it won’t, and killed it. * Go to the source. You don’t wait for a perfect PRD. You sit with PMs, designers, marketers, and data, and sometimes users directly, to understand what’s actually being asked. * Own things end-to-end. From the first conversation about a problem through architecture, code, rollout, monitoring, and the follow-up experiment. You don’t hand work off at a boundary. * Have a strong bias to ship. Prototypes, A/B tests, feature flags, kill switches. You’d rather get something in front of users this week than a perfect plan in two months. * Treat AI as leverage, not a novelty. You use agentic workflows to compress the loop between idea and learning, for yourself and the team.   What You’ll Own This is an ownership role, not a feature factory seat. You’ll be on the hook for outcomes across the stack, not just the code in your area: * A cross-platform foundation, end to end. Mobile, web, BFF, and infrastructure layers, built and evolved with an AI-first, agentic development approach, and held to outcomes you helped define. * Scalable foundations for health & fitness apps. React Native and modern web technologies, designed so product teams can ship and experiment faster without rederiving the basics each time. * The discovery loop with stakeholders. Working directly with product, design, marketing, and data to translate business bets into running experiments, not just tickets in a backlog. * AI-agentic workflows across the SDLC. You’ll continuously improve how the team uses AI to raise productivity, code quality, and delivery speed, and prove the impact. * Shared platform capabilities. Internal tooling, CI/CD pipelines, and AI-assisted workflows that make every engineer at Welltech faster and the product better. * Native mobile and media experiences. Video playback, streaming, and HLS, owned from native integration through user-perceived quality. * Modular, reusable systems. Backend-driven UI, white-label capabilities, and the architectural choices that let one team’s work compound for the next. * Reliable integrations. Between frontend clients, BFF services, and platform infrastructure, with you on the hook for the health of the seams. * The engineering culture. Architecture discussions, code reviews or pairing when working on trunk based development workflows, documentation, and continuous improvement, leading by what you ship and how you ship it.   WHAT WE’RE LOOKING FOR Key responsibilities: * Build and evolve a cross-platform ecosystem covering mobile, web, BFF, and infrastructure layers using an AI-first, agentic development approach * Design scalable foundations for health & fitness applications powered by React Native and modern web technologies * Work directly with product, design, and marketing stakeholders to rapidly translate business needs into scalable technical solutions and experiments * Develop and continuously improve AI-agentic workflows across the full development lifecycle to increase team productivity, code quality, and delivery speed * Develop shared platform capabilities, internal tooling, CI/CD pipelines, and AI-assisted workflows that improve development speed and product quality * Work on native mobile integrations and advanced media experiences, including video playback, streaming, and HLS-based solutions * Contribute to modular architectures, reusable systems, backend-driven UI solutions, and white-label application capabilities * Build reliable and scalable integrations between frontend clients, BFF services, and platform infrastructure * Participate in architecture discussions, code reviews, documentation, and continuous improvement of engineering workflows   Required skills: * Strong commercial experience with React Native and modern TypeScript-based application development * Solid understanding of full-stack architecture including mobile, web, BFF, and cloud/infrastructure layers * Experience building scalable cross-platform systems and shared application foundations * Deep understanding of software architecture, modular systems, scalability, and performance optimization * Experience working with CI/CD pipelines, automation tooling, and modern developer workflows * Strong engineering mindset focused on maintainability, reliability, testability, and fast iteration * Comfortable working in AI-assisted or agentic development environments and adopting new AI-driven workflows quickly * Experience with backend-driven UI architectures   Nice to have: * Experience building white-label mobile applications or multi-brand ecosystems * Experience designing and implementing BFF (Backend for Frontend) services * Hands-on backend development experience with TypeScript (Node.js) * Experience building internal developer platforms, shared tooling, or scalable platform capabilities * Familiarity with OWASP mobile security best practices * Experience with engineering methodologies focused on rapid iteration and high developer productivity (Trunk Based Development, CI/CD mindset, TDD, BDD, XP, etc.) * Strong experience with native mobile integrations and media/video playback technologies * Hands-on experience with HLS streaming and native video player integrations on iOS and Android (AVPlayer, ExoPlayer, Chromecast, AirPlay)   Candidate journey: ⭕️ Recruiter call --> ⭕️ Meet a Hiring Manager--> ⭕️ Skills assessment-->Live coding   Check out some of our products Muscle Booster — https://musclebooster.fitness/ Yoga-Go — https://yoga-go.io/ WalkFit - http://walkfit.pro