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 are looking for a Machine Learning Engineers to join Flo Health. You will be developing groundbreaking features that leverage our medical expertise, technical skills, rapid adoption of new technologies (like LLMs), product knowledge, and a deep understanding of our users’ needs. If you’re passionate about technology, especially advancements in generative AI, and driven by delivering value to users, we would love to hear from you!
Your Experience
Must have:
- 4+ years of professional experience in the field of machine learning
- Demonstrated success in building and deploying large-scale machine learning models; experience with large-scale LLM applications is a bonus
- Ability to devise creative solutions to intricate technical challenges, including experience in systems design with the ability to architect and explain ML/LLM pipelines
- Strong Python programming skills for efficient model development and deployment
- Experience with both traditional ML and modern LLM frameworks
- Understanding of the entire ML/LLM development process, including CI/CD, version control, testing, MLOps/LLMOps, and agile methodologies
- Experience in building and managing data pipelines using tools like Apache Spark
- Excellent communication skills and ability to collaborate with diverse teams
- Commitment to responsible AI practices, including fairness, accountability, and transparency
Nice to have:
- Advanced degree in Computer Science, Mathematics, or a related field
- Familiarity with statistical and measurement fundamentals and running and evaluating AB tests
- Data visualisation skills
- Experience in the MedTech domain
What you'll be doing
You'll be responsible for:
- Explore, develop and test complex ML/AI systems to improve female health
- Work with state-of-the-art technologies, such as most advanced LLMs and Generative AI approaches, to build solutions that are medically safe and work at scale
- Work in a fast-paced environment to quickly build and validate product hypotheses, taking end-to-end ownership of ML/AI products
- Build the future-proof infrastructure for serving Gen AI features at Flo, bringing our AI vision and strategy to life
- Constantly improve our technical capabilities by researching and implementing best practices in the context of the fastly evolving space of LLMs
- Work in a cross-functional setup alongside other engineering (ML, Backend, QA), product, and analytics teams
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.
Skills Required
- 4+ years of professional experience in machine learning
- Demonstrated success building and deploying large-scale machine learning models
- Ability to devise creative solutions to complex technical challenges
- Experience with systems design and architecting and explaining ML/LLM pipelines
- Strong Python programming skills for model development and deployment
- Experience with traditional machine learning and modern LLM frameworks
- Understanding of the end-to-end ML/LLM development process, including CI/CD, version control, testing, MLOps/LLMOps, and agile methodologies
- Experience building and managing data pipelines using tools such as Apache Spark
- Excellent communication and cross-functional collaboration skills
- Commitment to responsible AI practices, including fairness, accountability, and transparency
- Advanced degree in Computer Science, Mathematics, or a related field
- Familiarity with statistical and measurement fundamentals and running and evaluating A/B tests
- Data visualization skills
- Experience in the MedTech domain
Flo Health Inc. Compensation & Benefits Highlights
The following summarizes recurring compensation and benefits themes identified from responses generated by popular LLMs to common candidate questions about Flo Health Inc. and has not been reviewed or approved by Flo Health Inc..
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Parental & Family Support — Offerings include fully paid parental leave with additional support such as a return‑to‑work bonus and a dedicated policy for pregnancy loss. Coverage explicitly extends to adoptive and same‑sex parents, signaling inclusive family support.
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Leave & Time Off Breadth — Paid holiday and fully paid sick leave allocations are presented as substantial on top of local public holidays. This breadth indicates strong time‑off support relative to common market practices.
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Equity Value & Accessibility — Company‑wide eligibility for an employee share plan is highlighted as part of total rewards. Accessible equity participation can meaningfully augment overall compensation value.
Flo Health Inc. Insights
What We Do
Flo is the essential female health partner. We are building a better future for female health by helping women harness the power of their body signals. --------------- Flo in numbers: --------------- #1 period tracker in the USA by active audience #1 most downloaded female health app worldwide 47 million monthly active users 240 million installs 28M women got pregnant while using Flo (the number indicates users who logged pregnancy in app during 2015-2022) Flo prioritizes safety and keeps a sharp focus on being the most trusted digital source for women's health information. Flo intensively uses Data Science and AI to deliver the most personalized content and services available. Flo is currently available in 22 languages on iOS and Android. 55% of users are located in the US and Europe. We are committed to putting privacy of our users first. Our users trust our technology to keep their sensitive information private and we are responsible for providing a safe and secure platform for them to use. We regularly carry out privacy assessments to monitor risks including data protection impact assessments and third-party risk assessments. In March 2022 Flo completed an external, independent privacy audit which confirmed there are no gaps or weaknesses in our privacy practices.
