Principal DevEx 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 The Velocity team exists to eliminate friction. We treat our internal developers as our customers. You will: • Abstract Complexity: Build intuitive tooling that enables self-service allowing devs to focus on product logic. • Standardize Excellence: Bake best-practices, security, observability, and scalability into the core stack so they aren't afterthoughts. What You Will Do • Developer Experience: Build self-service tools that give product teams autonomy without sacrificing system stability. • Platform Engineering: Architect and evolve our core stack (AWS, EKS, Terraform). • Systems Resilience: Lead reliability initiatives, including business continuity planning and a sustainable on-call rotation. • High-Scale Privacy: Support the infrastructure for industry-leading privacy features, such as our TIME-recognized "Anonymous Mode." • Observability: Implement best-in-class monitoring (metrics, logs, tracing) to ensure issues are identified and mitigated before they impact the user. What You Bring • Experience: 15+ years in AWS Infrastructure, DevEx, SRE, or DevOps roles supporting high-traffic, distributed environments. • Cloud Native Mastery: Deep expertise in AWS and Kubernetes (K8s) is essential. • Automation Mindset: Proficient in Infrastructure as Code (Terraform), a coding background with experience with Python, Scala or Go would be beneficial. • Technical Breadth: You will feel comfortable at all levels of the stack, from developing front ends using React through to engineering Terraform modules to deliver infrastructure abstractions. • Communication: A "doc-first" mentality and the ability to collaborate across distributed product teams. AI First: You will have experience of the impact which AI automation is having on development teams and the software delivery lifecycle and have strong ideas on how to support them through it Bonus Points • Background in hardening infrastructure for high-compliance or security-sensitive environments. • Experience scaling consumer tech platforms with millions of concurrent users. • Professional Accreditation such as AWS Professional Architect, CKAD or KCSA. Why Join Flo? • High Impact: Flo is re-writing women’s health. • Autonomy: We hire experts and empower you to deliver. • Cutting-Edge Stack: Work with modern tools like Sentry, EKS, and Terraform in a fast-paced, "fail-forward" environment at a huge scale. 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 a