Lead Security Engineer

Location: London 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 About the role You’ll help Flo build a trusted, secure, audit-ready platform for the millions of people who use our women’s health app. You’ll support our SOC 2 Type II and ISO 27001 programs and help implement HIPAA safeguards, all within Flo’s integrated Information Security and Privacy Management System (ISPMS). This is a hands-on role. It needs strong applied security architecture skills, especially secure design reviews and technical control validation across AWS (EKS, Lambda, RDS, S3, VPC, IAM, KMS). You’ll work with our professional services partners, auditors, the Security team, and the Privacy, Product and Platform Engineering teams. Together you’ll design controls that reduce friction, so the business can move fast and stay secure. What you’ll do Support SOC 2 and ISO 27001 certifications and HIPAA safeguard implementation, and act as a point of contact for external auditors. Define and maintain security policies, standards and procedures. Help control owners put controls into practice and automate evidence gathering for audit readiness. Run technical design reviews and architectural risk assessments for AWS services, including data flows that handle PHI. Work with Engineering to harden AWS workloads (EKS, EC2, data pipelines) against industry best practices. Improve Flo’s security risk management framework, and track and report risks to leadership. Contribute to vendor risk management, including contract reviews and security assessments. Roll out security training and awareness campaigns. What you’ll bring 7+ years in security architecture, compliance or risk management. A degree in a related field is a plus. Hands-on experience with ISO 27001 and/or SOC 2 in a cloud-based SaaS environment. Familiarity with security controls for sensitive data. Experience with GRC and compliance automation platforms. The ability to manage several audit workstreams at once. Excellent communication skills, and the ability to turn compliance requirements into clear actions for engineering and business teams. Nice to have Working knowledge of the HIPAA Security Rule and PHI handling (highly valued). CISA, CISM or CISSP certification. Experience with NIST 800-53, CSA, CIS or HITRUST. A background in healthcare or another regulated industry. Experience building compliance roadmaps at a startup. Exposure to Kubernetes/Docker, serverless, big data platforms or DevSecOps. Experience with Agile delivery and vendor management. Annual Salary Range (ranges may vary based on skills and experience) £100,000 — £130,000 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 .