We\'re hiring a Data Science Lead in London to build and lead our Predictive Growth Optimization team - pioneering ML models that power our user acquisition strategy, predict lifetime value, and optimise our $25M+ annual marketing spend across channels. This role owns the strategy, development, and continuous improvement of Flo\'s pLTV system - a mission-critical model reused across UA, AdTech, personalization, and financial forecasting. You\'ll balance hands-on technical leadership with people management, building production systems that directly impact our growth trajectory.
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, we became the first product of our kind to reach a $1B valuation in 2024 - and we\'re not slowing down.
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.
Responsibilities
- Lead & develop a team of 4+ ML and Backend engineers - hiring, mentoring, and setting technical direction
- Own pLTV strategy - architect and evolve our core predictive lifetime value models that inform millions in UA decisions
- Build production ML systems - from MMM algorithms to real-time forecasting models handling millions of daily predictions
- Drive cross-functional impact - partner with Growth, Product, and Finance 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
Qualifications
- 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 (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
- Comfortable translating business requirements into technical roadmaps
- Strong communication skills - can explain complex models to executive stakeholders
- Production ML Systems
- Experience deploying ML models at scale (millions+ predictions/day)
- Knowledge of MLOps practices: model versioning, monitoring, automated retraining
- Understanding of data engineering fundamentals and cloud platforms
- 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
Benefits
- 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
