Frontend Engineer

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 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. Solid grasp of object-oriented design patterns and the ability to write efficient, well-structured algorithms You must use AI coding agents as your default way of working — writing code manually is the exception, not the rule. 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. Salary Range - gross per month (ranges may vary based on skills and experience) €5.900…