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
Flo is seeking an experienced candidate for a contracting role in human factors engineering. The job involves leading usability assessments and managing risk for medical devices, engaging with cross-functional teams, and contributing to regulatory submissions. This role will be embedded within a thriving and enthusiastic UX Research function!
This role is an excellent opportunity for an experienced Human Factors Engineer looking to take the lead on and work independently on a software as a medical device in women’s health.
Your Experience
Must have:
- Degree or higher in Human Factors Engineering, or relevant related subject
- Fluency and confidence understanding IEC 62366‐1, ISO 14971, and FDA regulations
- Significant experience conducting human factors research with software based medical devices that is compliant with IEC 62366‐1, ISO 14971, and FDA regulations
- Experience in creating and maintaining usability documentation to ensure compliance with IEC 62366‐1, ISO 14971, and FDA regulations
- Applied understanding of the product development process
- Applied understanding of medical device industry
- Relevant industrial experience commensurate with requirements of an experienced and independent contractor
- Exceptional attention to detail and precise data handling and analytical skills
- Technical report writing skills
- Exceptional time management skills and an ability to work well under pressure
Nice to have:
- Experience with software as a medical device in the women’s health space
- Experience conducting training on IEC 62366-1 and FDA Human Factors guidance, and practical implementation in a medical device environment
What you'll be doing
You'll be responsible for:
(1) Establishing Usability Engineering at Flo Health
- Assessing current development, design control, quality, and risk management processes to identify where usability engineering activities and artefacts should be embedded
- Defining a lean end-to-end usability engineering process, including activities, inputs/outputs, decision points, roles, responsibilities, and interfaces to risk management and design controls
- Defining the required usability engineering documentation and templates that comply with IEC 62366‐1, ISO 14971, and FDA regulations
(2) Conducting/Leading Formative and Summative Evaluations
- Maintaining and updating the Usability Engineering File
- Conducting the necessary formative evaluations to identify and mitigate use-related issues prior to summative testing
- Refining the critical task analysis, use-related risk analysis, and hazard-related use scenarios to ensure appropriate summative coverage
- Defining the summative evaluation scope, including device/product configuration(s), user groups, use environments, and critical tasks
- Creating the Summative Evaluation Protocol including acceptance criteria, sample size rationale, recruitment criteria, test scenarios, and success metrics
- Preparing all required summative testing materials, including moderator guide, participant materials, observation forms, and any other study documentation needed for execution
- Conducting the summative evaluation and documenting the results in a Summative Evaluation Report
- Assessing residual use-related risks and documenting conclusions and traceability within the usability engineering file
(3) Upskilling the UXR Team
- Coaching on how to conduct and document formative and summative evaluations and use-related risk activities
- Supporting the team in building reusable templates, checklists, and playbooks
Please note that this is a contractor role. As such, employee benefits do not apply.
#LI-Hybrid #LI-AJ1
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.
Flo Health Inc. London, England Office
London, United Kingdom, WC1N 3AX
