Engineering Manager - Data Science Team
Posted on November 23, 2025 (about 2 hours ago)
About Flo
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, the company became the first product of its kind to reach a $1B valuation in 2024. With 500 million+ downloads and 77 million+ monthly users, it has 6 million paid subscribers and the highest-rated experience in the App Store’s health category. Flo spends a decade earning trust at scale and is building the next generation of digital health powered by AI, privacy-first, and clinically backed to help users understand their bodies better.
The Job
Flo is not chasing product-market fit but has found it, being used by 1 in 4 women aged 18-44 in the US. They raised $200 million last year, with 8.6 million new installs and 2.8 million user growth earlier this year. The scale is engineered and increasingly predicted. This position is for a Data Science Lead in London to build and lead the Predictive Growth Optimization team, pioneering machine learning models that power user acquisition, predict lifetime value, and optimize $25 million+ annual marketing spend across channels. This role owns the strategy, development, and continuous improvement of Flo's predictive lifetime value (pLTV) system, a mission-critical model reused across user acquisition, AdTech, personalization, and financial forecasting. The role balances hands-on technical leadership with people management, building production systems impacting growth trajectory.
Responsibilities
- 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 that inform millions in user acquisition decisions
- Build production ML systems including MMM algorithms and real-time forecasting models handling millions of daily predictions
- Drive cross-functional impact by partnering with Growth, Product, and Finance teams to translate business problems into ML solutions
- Shape technical architecture focusing on MLOps infrastructure, monitoring, and rapid iteration cycles
- Stay hands-on contributing to modeling, architecture decisions, and technical problem-solving as needed
Requirements
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 (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 able to 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
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
Working Culture and Benefits
Flo is a mission-led, product-driven team moving fast, staying focused and taking ownership from brief to build to impact. They encourage debate and shared decisions, care about craft, and always raise the bar. The work environment values commitment, resilience, and drive for better health outcomes.
- 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 and home working, including up to 2 months a year working abroad
- 5-week fully paid sabbatical at 5-year anniversary
- Flo Premium for friends and family, plus more health, pension and wellbeing perks
Diversity, Equity and Inclusion
Flo commits to hiring based on merit, skill, and contributions to the role, welcoming applicants from all backgrounds. They are an equal opportunity employer.
How to Apply
You can apply through the application form on the job page. The application requires submission of personal details, resume/CV, cover letter, and LinkedIn profile. Additional questions about hands-on experience with advertising technologies, willingness to work on-site occasionally, and agreement with privacy policies are included.
Application Process
The application form mandates required fields such as first name, last name, email, and LinkedIn profile. Candidates must confirm they meet location and privacy notice requirements and agree to be contacted about job opportunities for up to 3 years.