Co-Founding CTO or CPO

At Sibyl, we're building the mental health infrastructure for the hardest parts of the reproductive journey, starting with the most acute and least served moment: pregnancy loss. 44 women lose a pregnancy every minute. A third meet PTSD criteria three months later. Care ends the day the loss is confirmed, usually with a pamphlet, and everything after (grief, return to work, the next pregnancy) is left to the woman to figure out alone. Sibyl closes that gap: a clinically grounded, always-available digital companion that extends care before, between, and long after appointments.

About Sibyl

The product is live with promising first signals. We need a co-founder to take it from a strong beta into category-defining infrastructure.

• Founder in place: Melissa Ablett-Jordaan, University of Wisconsin, former Global COO of Cambridge Innovation Center, built Sibyl from lived experience of pregnancy loss.
• Clinical and market bench built:
  • Catherine Chan, Fractional CFO (Babson, Philips, Sanofi Genzyme)
  • Dr. Heather Smith, OB-GYN Director of Quality (Women & Infants Hospital)
  • Dr. Jeanette Mayse, ABPP, Counseling Psychologist, Reproductive Mental Health
  • Dr. Shai Mahesh, Gynecologist and Fertility Specialist (MC Wetering)
  • Joan Zhang, exited digital health founder (Arise), product advisory
• D2C product live in the App Store with active subscriptions, following a closed beta of 130+ organic signups (no paid acquisition) and 87% signup-to-active conversion.
• Larger distribution conversations underway with established brands.
• B2B2C pilots running with gynecologists and midwives.
• Conversations underway with US fertility benefits providers and clinics.
• Real infrastructure: TypeScript/Bun, Postgres on GCP (EU-west4), direct Anthropic Claude API integration, GDPR-compliant by design, actively remediating toward HIPAA readiness for US expansion.
• $200K raised to date in a rolling pre-seed, targeting $500K.
• Accepted as an observer to the Springboard Enterprise Women's Health Accelerator Spring 2026 cohort.

The foundation is built and the need is proven. What's missing is a co-founder to own either the technical or product build at the level a category-defining company needs.

About the role

We're open to a technical or product-minded co-founder. Tell us where your edge is and we'll shape the role around it.

• If technical (CTO track):
  • Own the architecture as it scales from a single-region consumer app to a multi-tenant platform for health systems.
  • Own the compliance path (GDPR done, HIPAA next for US pilots already in the pipeline).
  • Own the AI layer, the personalization and memory system that is core IP.
  • Build the engineering team.
• If product-minded (CPO track):
  • Own the roadmap from acute-loss companion to the full reproductive journey (infertility, pregnancy after loss, postpartum).
  • Own the provider side, converting pilot interest into signed B2B2C partnerships.
  • Own the clinical bar with the advisory board.
  • Own growth, turning early signal into defensible retention and funnel.

Either track is build-first, full-ownership. You're in the room for every major decision from here.

Requirements

We hire on demonstrated capability, not years served.

• You've taken a product from early traction to real scale, as a founder, CTO, CPO, or founding engineer/PM at an early-stage startup.
• Experience building production-grade data infrastructure in a regulated or sensitive domain, or owning a roadmap from beta to commercial traction.
• You move fast without waiting for permission, and you understand what GDPR (and ideally HIPAA) means in practice, not just theory.
• Strongly preferred: experience in women's health, digital health, or mental health, and a real understanding of building for people in acute emotional distress.

Compensation

• Significant founding equity, standard 4-year vest, 1-year cliff.
• Minimal salary until pre-seed closes, founder-level after.
• Standard double-trigger acceleration.

Location

US, EU, or UK based, ideally US East Coast for overlap with Melissa in Rotterdam, the Netherlands.