About Flo
Flo is the world’s #1 health app on a mission to build a better future for female health. Backed by a $200M investment led by General Atlantic, it became the first product of its kind to reach a $1B valuation in 2024.
With 400M+ downloads, 75M+ monthly users, 6M paid subscribers, and the highest-rated experience in the App Store’s health category, Flo is now building the next generation of digital health — AI-powered, privacy-first, clinically backed — to help users know their body better.
The job
The Data Science Lead role in London is to build and lead the Predictive Growth Optimization team, pioneering ML models that power user acquisition strategy, predict lifetime value, and optimize a $25M+ annual marketing spend across channels.
This role owns the strategy, development, and continuous improvement of Flo's pLTV system, a mission-critical model used across user acquisition, AdTech, personalization, and financial forecasting. The role blends hands-on technical leadership with people management and building production systems to impact growth trajectory.
What you'll do
- Lead and develop a team of 4+ ML and Backend engineers — hiring, mentoring, and setting technical direction.
- Own pLTV strategy — architect and evolve core predictive lifetime value models informing millions in user acquisition decisions.
- Build production ML systems — including MMM algorithms to real-time forecasting models handling millions of daily predictions.
- Drive cross-functional impact — partner with Growth, Product, and Finance teams to translate business problems into ML solutions.
- Shape technical architecture — guide MLOps infrastructure, monitoring, and rapid iteration cycles.
- Stay hands-on — contribute to modeling, architecture decisions, and technical problem-solving as needed.
What you bring
Technical Leadership
- 7+ years applied ML experience building and deploying models in production.
- 4+ years managing technical teams (ML engineers, data scientists, or similar).
- Expert knowledge of ML fundamentals: supervised/unsupervised learning, time series, causal inference.
- Experience with modern ML frameworks like PyTorch, TensorFlow, scikit-learn, CatBoost.
Growth & Product Experience
- Experience with growth analytics, attribution modeling, or marketing effectiveness.
- Understanding of user acquisition funnels and retention optimization.
- Skillful at translating business requirements into technical roadmaps.
- Strong communication skills to explain complex models to executive stakeholders.
Production ML Systems
- Experience deploying ML models at scale (millions+ predictions/day).
- Knowledge of MLOps practices including model versioning, monitoring, automated retraining.
- Understanding of data engineering fundamentals and cloud platforms.
Nice to have
- Experience with Marketing Mix Modeling, attribution, or ad tech.
- Background in consumer tech, mobile apps, or health tech.
- Knowledge of privacy-preserving ML techniques and A/B testing methodology.
How we work
Flo is a mission-led, product-driven team that moves fast, stays focused, and takes ownership — from brief to build to impact.
The team values debate and shared decisions, cares about craft, ships with purpose, and consistently raises the bar.
Team members take their work seriously but not themselves, emphasizing commitment and resilience for better health outcomes.
What you'll get
- 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 impactful work and learning support.
- Flexible office + home working and up to 2 months per year working abroad.
- 5-week fully paid sabbatical at 5-year Floversary.
- Flo Premium for friends and family, plus health, pension, and wellbeing perks.
Diversity, equity and inclusion
Flo values differences and hires based on merit and skill without discrimination.
Flo is an equal opportunity employer welcoming applicants from all backgrounds and identities.
Applicants can review the privacy notice for job applicants at https://flo.health/privacy-policy-for-job-applicants.