Senior/ Lead Android Engineer

Senior/ Lead Android Engineer

Location: London Department: Engineering

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

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.