500M+ downloads. 77M+ 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 6M 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
We’re looking for a Senior Frontend Engineer to help us build the next generation of Flo’s platform and user experiences.
You’ll work on the foundation that powers interactive surveys and dynamic content inside the Flo app — building SDKs, reusable components, and internal tooling that enable other product teams to deliver exceptional experiences quickly and reliably.
Our frontend stack is based on React, TypeScript, and Next.js, with a strong focus on performance, maintainability, and testing.
We care deeply about quality: we use TypeScript for type safety, Jest and Playwright for automated testing, and continuously evolve our design system and UI Kit.
What you'll be doing:
- Design, build, and maintain high-quality user-facing components and platform SDKs that enable survey and interactive experiences in the Flo ecosystem.
- Collaborate with product, design, and backend engineers to deliver flexible and scalable solutions.
- Contribute to Flo’s design system and shared UI libraries, ensuring consistency and reusability across products.
- Refactor and improve existing codebases for performance, reliability, and maintainability.
- Write clean, modular, well-documented code and advocate for engineering best practices.
- Actively participate in the frontend community at Flo, sharing ideas and driving improvements in architecture and development processes.
Your Experience
Must have:
- 7+ years of experience building, shipping, and maintaining modern web applications.
- Expert-level knowledge of HTML, CSS, and JavaScript (ES6+).
- Deep experience with React and modern frontend tooling.
- Proven ability to create adaptive, responsive, and accessible user interfaces.
- A product mindset and strong collaboration skills — you care about how your work impacts the user.
Nice to have:
- Familiarity with Next.js, Contentful, or similar frameworks and CMS solutions.
- Experience with A/B testing and experimentation frameworks.
- Understanding of analytics and BI integrations.
- Exposure to continuous delivery pipelines and web automation tooling.
- A good sense of design and usability.
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
- Flexible office + home working, up to 2 months a year working abroad
- 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.
Top Skills
What We Do
Flo is the essential female health partner. We are building a better future for female health by helping women harness the power of their body signals.
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Flo in numbers:
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#1 period tracker in the USA by active audience
#1 most downloaded female health app worldwide
47 million monthly active users
240 million installs
28M women got pregnant while using Flo (the number indicates users who logged pregnancy in app during 2015-2022)
Flo prioritizes safety and keeps a sharp focus on being the most trusted digital source for women's health information.
Flo intensively uses Data Science and AI to deliver the most personalized content and services available.
Flo is currently available in 22 languages on iOS and Android. 55% of users are located in the US and Europe.
We are committed to putting privacy of our users first. Our users trust our technology to keep their sensitive information private and we are responsible for providing a safe and secure platform for them to use. We regularly carry out privacy assessments to monitor risks including data protection impact assessments and third-party risk assessments. In March 2022 Flo completed an external, independent privacy audit which confirmed there are no gaps or weaknesses in our privacy practices.
