Lead Data Engineer

Flo Health

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 We’re hiring a Data Science Lead in London to build and lead our Predictive Growth Optimisation 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, personalisation, and financial forecasting. That is the core of the role. Alongside it, you'll stand up a Marketing Mix Modeling (MMM) capability to measure cross-channel effectiveness and inform budget allocation, and develop the algorithms to drive real-time UA campaign management. You'll lead a team building production systems that directly impact our growth trajectory, staying as hands-on as you choose. WHAT YOU’LL DO * Lead & develop a team of 6+ 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 * Stand up MMM - build our Marketing Mix Modeling capability: adstock and saturation modelling, channel contribution, and budget allocation, calibrated against our incrementality experiments * Power real-time campaign management - develop the algorithms that optimise our UA campaigns across channels in real time * Build production ML systems - from real-time prediction services handling millions of daily predictions to MMM models * 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 as hands-on as you choose - modeling, architecture decisions, technical problem-solving; your call how deep you go. 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; strong grounding in causal inference * Experience with modern ML frameworks (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 * Knowledge of MLOps practices: model versioning, monitoring, automated retraining * Understanding of data engineering fundamentals and cloud platforms NICE TO HAVE * Hands-on experience building Marketing Mix Models end to end, Bayesian or regression based * Background in consumer tech, mobile apps, or health tech * Knowledge of privacy-preserving ML techniques and A/B testing methodology 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.

Liberis

Some key info for you about Liberis:  🌱 We were founded in 2007 💰 We have provided over $3bn of funding to small businesses so far 🚀 We have been named in CNBC & Statista Top 150 UK Fintechs for 2025 🌍 We're a global team, with a dynamic presence in 6 key locations around the world 🧠 We're a thriving community of over 290 innovative minds 👩🏾 🤝 👨🏼 We're a vibrant melting pot, celebrating over 27 nationalities in our team 🏢 Our team brings experience from over 740 previous companies, from startups to global giants 🎯 We have just been named as one of FinTech’s Finest 50 by Welcome to the Jungle 💪 We’re proud to be an accredited Real Living Wage employer, ensuring everyone is paid fairly for the great work they do!   Our Product & Engineering Team: Liberis is building the embedded finance platform that lets partners around the world offer innovative funding products to their small business customers. We're a growth-stage fintech with teams in London, Nottingham, Atlanta, Stockholm, Munich and Mumbai, and we’re building a global Product, Data & Engineering team that thrives on autonomy, ownership, and is focused on impact! Our teams solve real-world problems for small businesses, shaping products that unlock opportunity at scale. Engineering is going through an AI-first transformation, rethinking how teams are structured and how they ship. It's changing what a small team can do! We empower our teams to make decisions, move fast, and take full responsibility for the solutions they deliver. You’ll join a team where curiosity is encouraged and collaboration across Product, Data, Delivery and Engineering is the norm.   The role: Joining our Cloud Platform team as a Lead DevEx Engineer, you will play a key role in improving how engineers build, ship and operate services across Liberis. This is a brand new role created to bridge the gap between application development and platform engineering - creating a more consistent, scalable developer experience as we continue to evolve our platform strategy. You will focus on building for engineers - creating and shaping the templates, standards and foundations used across services. Alongside this, you will have the opportunity to contribute to emerging platform initiatives, including work that supports AI enablement across the engineering organisation.  This is a high-impact role with real scope to influence how engineering works at Liberis!   What you'll get to do in the role: * Own and evolve the service template library for .NET, Node.js, and Python — covering project scaffolding, dependency management, containerisation, local dev setup, and production configuration. Templates are generated, not forked, so keeping them current and opinionated matters. * Build and maintain CI/CD pipeline templates in GitHub Actions and/or Azure DevOps, covering build, test, security scanning, and deployment — consistent across stacks and reusable across teams. * Define and ship observability standards: structured logging, distributed tracing, and alerting integrated into service templates so every new service is production-ready from day one. * Work hands-on with Datadog, incident.io, and/or GCP/Azure-native logging and monitoring tooling to build the platform-level observability layer teams plug into. * Contribute to our thinking on a potential Azure-to-GCP migration — helping assess what changes for developer tooling and service templates and building proof-of-concept work that informs the decision. * Partner with product engineers to understand where developer experience breaks down — slow pipelines, confusing templates, missing runbooks — and fix the root causes, not the symptoms. * Lead technical decisions on platform tooling: evaluate new tools, write ADRs, and drive adoption of improvements across multiple engineering teams. * Mentor engineers in the Cloud Platform team and act as a go-to resource for product engineers getting to grips with platform tooling.   The interview process: * Screening call with Chess (Internal Recruiter) (30 mins) * Video interview with the Hiring Manager (45 mins) * In person code pairing interview with a member of Engineering team (1 hour) * Video interview with the wider Liberis team (1 hour)   What we think you'll need: * Proficient in at least one of .NET (C#), Node.js and Python — able to build, configure, and template production-grade services in each. * Strong GCP experience (Azure experience is nice to have) * Hands-on experience designing reusable CI/CD pipeline templates — GitHub Actions or Azure DevOps — consistent across stacks and teams. * Comfortable with containerisation (Docker) and deployment on Kubernetes or Cloud Run. * Observability experience with at least one of: Datadog, incident.io, or cloud-native logging and monitoring (GCP Cloud Operations or Azure Monitor). * Infrastructure-as-code with Terraform. * A proven track record of driving adoption — building things engineers use, writing docs that get read.   Career development is really important to us here at Liberis, with progression opportunities for both individual contributors and people managers. You can have a look through our Engineering Career Framework via this link  Our hybrid approach Working together in person helps us move faster, collaborate better, and build a great Liberis culture. Our hybrid working policy requires team members to be in the office at least 3 days a week. At Liberis, we embrace flexibility as a core part of our culture, while also valuing the importance of the time our teams spend together in the office. #LI-FC1

Liberis

Some key info for you about Liberis:  🌱 We were founded in 2007 💰 We have provided over $3bn of funding to small businesses so far 🚀 We have been named in CNBC & Statista Top 150 UK Fintechs for 2025 🌍 We're a global team, with a dynamic presence in 6 key locations around the world 🧠 We're a thriving community of over 290 innovative minds 👩🏾 🤝 👨🏼 We're a vibrant melting pot, celebrating over 27 nationalities in our team 🏢 Our team brings experience from over 740 previous companies, from startups to global giants 🎯 We have just been named as one of FinTech’s Finest 50 by Welcome to the Jungle 💪 We’re proud to be an accredited Real Living Wage employer, ensuring everyone is paid fairly for the great work they do!   Our Product & Engineering Team: Liberis is building the embedded finance platform that lets partners around the world offer innovative funding products to their small business customers. We're a growth-stage fintech with teams in London, Nottingham, Atlanta, Stockholm, Munich and Mumbai, and we’re building a global Product, Data & Engineering team that thrives on autonomy, ownership, and is focused on impact! Our teams solve real-world problems for small businesses, shaping products that unlock opportunity at scale. Engineering is going through an AI-first transformation, rethinking how teams are structured and how they ship. It's changing what a small team can do! We empower our teams to make decisions, move fast, and take full responsibility for the solutions they deliver. You’ll join a team where curiosity is encouraged and collaboration across Product, Data, Delivery and Engineering is the norm.   The role: Joining our Cloud Platform team as a Lead DevEx Engineer, you will play a key role in improving how engineers build, ship and operate services across Liberis. This is a brand new role created to bridge the gap between application development and platform engineering - creating a more consistent, scalable developer experience as we continue to evolve our platform strategy. You will focus on building for engineers - creating and shaping the templates, standards and foundations used across services. Alongside this, you will have the opportunity to contribute to emerging platform initiatives, including work that supports AI enablement across the engineering organisation.  This is a high-impact role with real scope to influence how engineering works at Liberis!   What you'll get to do in the role: * Own and evolve the service template library for .NET, Node.js, and Python — covering project scaffolding, dependency management, containerisation, local dev setup, and production configuration. Templates are generated, not forked, so keeping them current and opinionated matters. * Build and maintain CI/CD pipeline templates in GitHub Actions and/or Azure DevOps, covering build, test, security scanning, and deployment — consistent across stacks and reusable across teams. * Define and ship observability standards: structured logging, distributed tracing, and alerting integrated into service templates so every new service is production-ready from day one. * Work hands-on with Datadog, incident.io, and/or GCP/Azure-native logging and monitoring tooling to build the platform-level observability layer teams plug into. * Contribute to our thinking on a potential Azure-to-GCP migration — helping assess what changes for developer tooling and service templates and building proof-of-concept work that informs the decision. * Partner with product engineers to understand where developer experience breaks down — slow pipelines, confusing templates, missing runbooks — and fix the root causes, not the symptoms. * Lead technical decisions on platform tooling: evaluate new tools, write ADRs, and drive adoption of improvements across multiple engineering teams. * Mentor engineers in the Cloud Platform team and act as a go-to resource for product engineers getting to grips with platform tooling.   The interview process: * Screening call with Chess (Internal Recruiter) (30 mins) * Video interview with the Hiring Manager (45 mins) * In person code pairing interview with a member of Engineering team (1 hour) * Video interview with the wider Liberis team (1 hour)   What we think you'll need: * Proficient in at least one of .NET (C#), Node.js and Python — able to build, configure, and template production-grade services in each. * Strong GCP experience (Azure experience is nice to have) * Hands-on experience designing reusable CI/CD pipeline templates — GitHub Actions or Azure DevOps — consistent across stacks and teams. * Comfortable with containerisation (Docker) and deployment on Kubernetes or Cloud Run. * Observability experience with at least one of: Datadog, incident.io, or cloud-native logging and monitoring (GCP Cloud Operations or Azure Monitor). * Infrastructure-as-code with Terraform. * A proven track record of driving adoption — building things engineers use, writing docs that get read.   Career development is really important to us here at Liberis, with progression opportunities for both individual contributors and people managers. You can have a look through our Engineering Career Framework via this link  Our hybrid approach Working together in person helps us move faster, collaborate better, and build a great Liberis culture. Our hybrid working policy requires team members to be in the office at least 3 days a week. At Liberis, we embrace flexibility as a core part of our culture, while also valuing the importance of the time our teams spend together in the office. #LI-FC1