Senior Android Engineer

Marshmallow

We’re on a mission to make migration easy. We started building Marshmallow in 2017. Since then, we’ve grown from 3 to 700+ people, gained unicorn status, raised ~£140M over three funding rounds, turned profitable, insured millions of drivers and lent millions in car loans. But we’re only just getting started. Our goal is to become one of the largest financial services providers in the world. Over the next 10 years we’ll grow exponentially, not only by scaling our existing products, but also by building new ones. To achieve our goals we need incredibly ambitious, commercially driven people who never settle for ‘good enough’. Marshmallowers are hungry for autonomy and ownership, and would rather improve than coast. Everyone raises standards and has an impact, with a focus on collective success over self-interest. We’ve created an environment where curious, tenacious people win and grow together. If that sounds motivating, this could be the place for you. (HYBRID - 3 DAYS A WEEK IN OUR LONDON OFFICE) ENGINEERING AT MARSHMALLOW Our engineers are at the heart of the solutions. They work on product builds from start to finish, solving lots of challenges to help us build fast, and scale up! Our engineers cover a range of skills across frontend, backend, full stack, iOS and Android, and work alongside designers, data scientists, researchers and product managers within our product teams. Our product teams include: the Renewals team, Telematics team and the Claims team (to name a few!) Each team sets its own roadmap and QBRs, and actively pushes our codebase forward. Learn more about our teams and how our engineers work here! THE TEAM YOU'D BE JOINING We're looking for a driven and curious senior Android engineer to join the New Financial Products Team as we embark on one of Marshmallow's most ambitious chapters. In 2026, the team is focused on transforming Marshmallow from a car insurance and car finance provider into a high-engagement financial companion for migrants in the UK — and your work will sit at the heart of that mission. This role directly supports our foundational strategic pillar for 2026: building the product and data capabilities that will unlock multi-product growth, deeper customer understanding, and new revenue streams over time. What you'll be doing * Join a team operating in new territory for Marshmallow. You'll help define what to build, pivot when priorities shift, and take initiative without waiting to be asked * Own significant parts of our Android codebase end-to-end, establishing yourself as the go-to expert for core components and systems while actively raising the technical bar for those around you * Shape how we build, not just what we build. You’ll partner with engineering and product leadership to define the technical roadmap and influence architectural decisions that will underpin Marshmallow's next chapter * Design and ship high-quality Android solutions using modern practices (Jetpack Compose, MVVM/MVI, Kotlin Coroutines, robust CI/CD) — embracing AI tooling to accelerate development, and writing code that is simple, well-tested, and built to scale * Lead medium to large projects across multiple engineers, breaking ambiguous problems into clear milestones and driving delivery with the kind of ownership that others can depend on * Drive improvements to tooling, processes, and engineering culture proactively, using data to cut through ambiguity and making the team measurably faster and higher quality over time Who are you * You thrive under pace and know how to make smart trade-offs. You weigh up risk, cut through noise, and keep delivery moving without sacrificing quality * You don't wait for problems to come to you. You spot them early, solve them proactively, and bring others along with you * You embrace change and actively seek out new tools and approaches to raise the quality and pace of what your team ships * You build trusted relationships naturally, working across product, design, and backend teams with a collaborative mindset and a shared sense of ownership over outcomes * You bring your engineering perspective into product conversations, using technical insight to challenge assumptions, spot opportunities, and help shape decisions before they become requirements What we're looking for from you * Strong commercial Android development experience, with a strong command of Kotlin and hands-on experience with Jetpack Compose and Kotlin Coroutines * A track record of shipping high-quality apps to the App Store and Google Play Store * Experience working in cross-functional teams alongside product, design, and fellow engineers to align on objectives and drive outcomes * A commitment to writing maintainable, well-tested code that enables safe and efficient development practices * Collaborates with designers and Product Managers early and often to influence how ideas take shape, ensuring decisions are grounded in real-world mobile constraints and user experience. Our Tech Stack * All new features are built in Kotlin, Jetpack Compose and Coroutines * Access to Claude Code to help engineers move faster on boilerplate, debugging, and code review. * Code is organised into local Gradle feature modules to help keep it maintainable and scalable. * We use automation as much as possible when it comes to testing our app, writing unit tests for business logic, snapshot tests for UI and automated UI tests for user interaction. * Our continuous integration tool of choice is Bitrise * We review each other's code using GitHub and automate as much of our code styling as possible using tools like lint and detekt. We are committed to fostering the professional growth of our team members and are open to coaching Android engineers who are interested in expanding their skill sets in backend or full stack technologies. We believe in providing a supportive environment where continuous learning is encouraged, and we are happy to facilitate training and mentorship opportunities to help you achieve your career goals. PERKS OF THE JOB * Bonus scheme designed to reward high performance * Private medical insurance with Vitality, mental health support with Oliva * Personal learning budget and 2 dedicated L&D days a year * Monthly flexible benefits budget to spend as you choose * 25 days holiday plus bank holidays * 4 weeks Work From Anywhere per year OUR PROCESS * Initial call with a member from our Talent Team (30 mins) * Past Experience interview with Hiring Manager & GM of New Financial Products (30-45 mins) * Android technical skills case study and interview with a couple of the team (120 mins) * Culture interview (60 mins) We’ll let you know if you’re invited to an interview or not. But, as a small team with a lot of applications to consider, we can’t give individual feedback on each application. Diversity of thought We know the best ideas come from having different perspectives in the room - and we're committed to hiring fairly, regardless of background, identity or experience. If you see yourself in this role, we'd encourage you to apply. Diversity of thought We know the best ideas come from having different perspectives in the room - and we're committed to hiring fairly, regardless of background, identity or experience. If you see yourself in this role, we'd encourage you to apply.

Proton

Join Proton and build a better internet where privacy is the default Proton was founded in 2014 by scientists from CERN on a simple truth: privacy is a fundamental human right. Since then, we’ve built the world’s largest encrypted email service (Proton Mail) and expanded into Proton VPN, Proton Drive, Proton Pass, and Proton Calendar—tools used by millions globally to protect their freedom, fight censorship, and keep their data safe. In some situations, Proton has literally helped save lives! We are profitable, independent (no VC control), and selectively hire from the top ~1% of applicants. Our 500+ team members across 50+ countries come from leading organizations and elite academic backgrounds. We move fast, keep hierarchy light, and prioritize impact over optics. If you want to do meaningful work with exceptionally high-caliber people, this is it. Join us and do work you can truly be proud of. Check our open-source projects here! About Photos Join the team building Proton Drive Photos, a private photo storage designed so your memories belong only to you. We’re creating the encrypted alternative to Big Tech photo platforms, combining consumer-grade UX with uncompromising privacy. If you want to build products used by millions while helping fix the internet, we’d love to meet you. Role overview As a fullstack cross-platform Android Engineer, you'll play a pivotal role in developing Proton Photos using Jetpack Compose and Rust. You’ll use an end-to-end ownership approach, ensuring timely delivery of high-quality, scalable solutions that will delight our customers.  Key responsibilities * Develop and maintain cross-platform mobile applications for Android using a blend of cross-platform (Rust) and native technologies (Kotlin) * Take end-to-end ownership of mobile application development projects: you'll be comfortable with scoping projects, walking back from deadlines and being able to discern the important from the superfluous * Foster a culture of innovation by exploring new technologies, methodologies and approaches to mobile development – we tackle complex engineering challenges with creativity and ingenuity * Optimise mobile applications for performance, usability and responsiveness across different devices and screen sizes * Master memory management, multithreading and concurrency mechanisms to enhance performance and responsiveness of mobile applications * Design for scalability, considering factors such as data caching, network bandwidth and server load * Prioritise customer satisfaction by maintaining a customer-centric mindset throughout the development process, continuously seeking feedback and iterating to improve the user experience The ideal candidate will bring * Bachelor's degree in Computer Science, Engineering or related field (or equivalent work experience) * Excellent problem-solving skills and the ability to think outside the box to overcome challenges * Passion for continuous learning and driving change in the rapidly evolving field of mobile development * Excellent communication and interpersonal skills * Proven experience developing mobile applications for Android using Kotlin * Proficiency with Jetpack Compose for Android, and familiarity with Rust * Strong understanding of mobile app architecture, design patterns and best practices * Knowledge of memory management techniques and best practices * Experience with multithreading and concurrency in mobile applications * Good understanding of scalability considerations when it comes to engineering mobile applications * Previous experience working in a fast-paced, scale-up environment Even if you don’t meet all the requirements listed above but feel you could still be a great fit, please do apply. What we offer * Technology: we provide all the devices and software you need to excel in your role, ensuring you have the best tools at your disposal to achieve your goals * Learning & Development: we are committed to your professional growth – Proton offers various learning opportunities, including training programs, conferences/events and continual learning * Employee Benefits: comprehensive health insurance plans, competitive retirement savings options, generous vacation/leave policies and wellness programs * Stock Options: at Proton, we are all owners of the company and you get stock options when you join us * In-Person Collaboration: collaboration is easier and more effective in person, which is why we have offices in Geneva, Zurich, Prague, Barcelona, Paris, London, Vilnius, Skopje and Taipei – you can enjoy working from home for up to 30% of the time, while enjoying great company culture during our three core days in the office * Food: lunch and snacks are provided by Proton every day at our offices * Transport: we'll always support our employees with transport costs through subsidising public transport, bike allowances or parking spaces based on your office location * Flexible Working: you can define your own working hours as long as it works with team meetings * Work that Matters: Proton is a community-first organisation, started with the support of a crowdfunding campaign and built with community input – to this day, Proton’s only source of revenue is user subscriptions: over 100 million people trust and support Proton, and we put our users and community first in everything we do (read more about our impact here) Our commitment to diversity and inclusion At Proton, we believe diversity drives innovation and strengthens our mission to provide privacy as a default for all. We are committed to fostering an inclusive environment where all individuals, regardless of race, ethnicity, gender, age, sexual orientation, physical ability or socio-economic background feel valued and empowered. We strive to create equal opportunities, promote open dialogue and support continuous learning to ensure every voice is heard and respected. If you need any extra support or reasonable adjustments during the hiring process, please let your talent partner know. Candidate privacy notice When you apply for a position, refer a candidate or are considered for a role at Proton Technologies AG (Proton, we, us or our), your information is stored in Greenhouse, in accordance with its Service Privacy Policy. This information is used to evaluate your suitability for the posted position. We also retain this information for consideration for future roles that you may apply for or that we believe may align with your background and skills. If we no longer have a legitimate business need to process your information, we will either delete or anonymise it. Should you have any inquiries about how we use or manage your information or if you wish to access, correct or delete your data, please contact our privacy team at careers@proton.ch. Proton does not accept unsolicited CVs from any sources other than directly from candidates. We will not pay a fee for any placement resulting from an unsolicited offer, even if the candidate is subsequently hired by Proton. To learn more about our privacy policy, please visit our privacy policy page. #LI-ONSITE

Flo Health

500M+ downloads. 80M+ monthly users. A decade of building – and we’re still accelerating. Flo is the world’s #1 health & fitness app worldwide on a mission to build a better future for female health. Backed by a $200M investment led by General Atlantic, we became the first product of our kind to reach a $1B valuation in 2024 – and we’re not slowing down. With 7M paid subscribers and the highest-rated experience in the App Store’s health category, we’ve spent 10 years earning trust at scale. Now, we’re building the next generation of digital health – AI-powered, privacy-first, clinically backed – to help our users know their body better. The job As an Android Engineer at Flo, you'll help shape the mobile experience for millions of people, and do genuinely meaningful work in women's health. Our app is trusted by 1 in 4 women aged 18–44 in the US and used across 100+ countries, with machine learning and AI powering accurate cycle predictions and personalised, medically credible health insights. We build large-scale mobile applications with rich, intuitive interfaces - optimised for speed, accessibility and privacy. You'll join a cross-functional team working across the full mobile lifecycle, from feature ideation through to release and iteration, with real ownership over value delivery end to end. We're not a feature factory. Our engineers are pragmatic problem-solvers who thrive in fast-moving environments and care about what they ship. You'll have genuine scope to experiment, lead ambitious product initiatives and implement solutions that matter - not just clear a backlog. Flo is a constantly evolving product, and we give our engineers the trust and autonomy to evolve it. Your Experience Must have: * 7+ years of hands-on Android development experience, with a track record of shipping and maintaining production applications at scale * Experience building large, complex mobile applications with polished, performant UIs - ideally for global consumer audiences * Strong proficiency in Java, with solid object-oriented design principles and a keen eye for clean, maintainable code * Deep knowledge of the Android ecosystem - including platform fragmentation, UI design patterns, and delivering consistent experiences across a wide range of screen sizes and devices * Solid familiarity with Google technologies, Play Store submission processes, and Google's development guidelines * A good grasp of the full mobile product lifecycle, with practical experience working within Agile teams Nice to have: * Knowledge of Kotlin programming language, Clean Architecture and reactive programming * An eye for UX and interaction design - you care about how things feel, not just how they work * Hands-on experience with mobile CI/CD tooling, including build, test and release automation * Experience integrating with analytics and BI systems, including A/B testing frameworks * Experience with alternative Android markets * Experience optimising data usage over mobile networks and building offline-first applications What you'll be doing You'll be responsible for: * Developing features using modern frameworks, libraries and in-house components - contributing to a shared codebase built to last * Delivering polished, intuitive user experiences that meet a high bar for design and usability * Maintaining and improving a continuous delivery pipeline, ensuring fast, reliable and safe releases to production #LI-Hybrid #LI-AJ1 Annual Salary Range (ranges may vary based on skills and experience) £95,000—£120,000 GBP How we work We’re a mission-led, product-driven team. We move fast, stay focused and take ownership – from brief to build to impact. Debate is encouraged. Decisions are shared. We care about craft, ship with purpose, and always raise the bar. You’ll be working with people who take their work seriously, not themselves. It takes commitment, resilience, and the drive to keep going when things get tough. Because better health outcomes are worth it.  What you'll get We support impact with meaningful reward. Here’s what that looks like: * Competitive salary and annual reviews * Opportunity to participate in Flo’s performance incentive scheme * Paid holiday, sick leave, and female health leave * Enhanced parental leave and pay for maternity, paternity, same-sex and adoptive parents * Accelerated professional growth through world-changing work and learning support * In-person collaboration and work in a hybrid model, with 3 days per week spent in the office * 5-week fully paid sabbatical at 5-year Floversary * Flo Premium for friends & family, plus more health, pension and wellbeing perks Diversity, equity and inclusion Our strength is in our differences. At Flo, hiring is based on merit, skill and what you bring to the role – nothing else. We’re proud to be an equal opportunity employer, and we welcome applicants from all backgrounds, communities and identities. Read our privacy notice for job applicants.