Founding Engineer - Path to CTO

This role depends on us closing our current funding round.

femmli is building continuous hormone intelligence for women navigating perimenopause through a wearable biosensor and AI-powered app that identifies personalized patterns, and delivers actionable insights.

Perimenopause affects 45M+ women in the U.S., yet clinicians can’t measure hormonal fluctuations driving it. Today's standard of care relies on episodic blood draws that capture a single point in a years-long transition. Women experiencing 30+ symptoms are told their hormone levels are "within range" and sent home without answers.Women are most affected during the peak of their careers, resulting in $25B+ medical costs and $1.8B in lost productivity per year. femmli exists so they don't have to figure it out by themselves. We're a small team of scientists, strategists, and builders making that happen.

Our wireframe is complete, and we're now looking for a founding engineer to build the production mobile app, architect the backend and data infrastructure that will ingest and process continuous biosensor data, and integrate with third-party wearables.
This is a founding, CTO-track role: you'll set the technical direction and architecture for femmli from the ground up, make the foundational decisions that our future engineering team will build on, and grow into the company's technical leadership as we scale. We're looking for someone who has done this before - or who has the technical depth and judgment to be ready to.

What you'll do:

• Design and build femmli's cross-platform mobile app from our completed wireframe, architecting for continuous biosensor data ingestion and offline resilience
• Design UI that's clean, accessible, and on brand
• Own the architecture, implementation and evolution of the platform, and implement access controls that meet HIPAA standards for PHI. This is core to the product, and we'll support you in getting up to speed on the regulatory specifics
• Connect the app to wearables and other health data sources
• Guide the technology choices and roadmap, define coding standards and engineering practices, including efficient AI-native SDLC, and help shape the future technology organization
• Make sure everything meets HIPAA standards for handling PHI (we'll help you get up to speed if you need it)
• Set the technical roadmap and make the big architecture calls
• Design and build a high-performance, secure, scalable, cloud-native system that can handle large volumes of sensitive and health data.
• Architect the backend services and data layer that power femmli's hormone analytics platform, ensuring the system can scale from beta to full launch without a rebuild.
• Work closely with our designers and the founding team

What we're looking for:

• Strong with React and React Native, Flutter, or similar. Comfortable on the back development - Node, Python/Django, whatever you're strongest in. You've shipped apps to TestFlight and Google Play before. Experience building, managing, scaling and securing applications on AWS (including encryption at rest/in transit, IAM/least-privilege access, audit logging, BAA-aware architecture, infrastructure-as-code, and monitoring/observability). Experience with SQL and NoSQL databases, and preferably time-series or streaming data. Ability to use AI-driven development safely and thoughtfully to accelerate product delivery and ensure user satisfaction. Experience with wearable integrations (Apple Health, Oura, Whoop) and FHIR/HL7 and HIPAA is strongly preferred.
• Nice to have: CTO or founding engineer experience, experience turning a web app or wireframe into a native app, or a background in digital health or women's health.

Who you are:
You care about this mission. You're thoughtful, you communicate well, and you're comfortable with the uncertainty that comes with building something early. You are a hands-on, experienced zero-to-one builder, who wants ownership, thrives in autonomy, and has the ability to deliver efficiently with minimum direction, and is ready to lead on the technical side as we grow.

Why this role:
You'll have real influence over the technical direction of a company built to help women. You'll be part of a small, values-driven team, with access to networks like MIT, and compensation that reflects the level of ownership you're taking on.