SiPhox Health

Wearable and At-Home health monitoring with silicon photonic chips

About SiPhox Health

SiPhox is a series B-stage startup building frictionless blood testing for AI healthcare. We combine silicon photonics, microfluidics, embedded systems, and semiconductor-grade manufacturing to quantify multiple biomarkers in minutes on a coffee-maker-sized device. Our goal is to build the first mass-market photonic blood analyzer and dramatically expand access to precision diagnostics.

We are already in the market serving 10s of thousands of customers with a category-leading mail-in blood test, with 3x YoY revenue growth.

Our mission is simple but ambitious: make healthcare proactive instead of reactive by enabling people to measure their health frequently, easily, and affordably.

The Role

We're hiring a Director of Finance to run finance the way a great operator runs a factory — close to the metal, suspicious of every recurring line item, and ruthless about cash.

This is not a fundraising-deck role. It's not a controller role. It's a wartime operating role for someone who treats burn rate like oxygen, knows every vendor and headcount line by name, and protects each dollar as if it were their own — while still moving fast enough to enable aggressive execution.

Hardware companies bleed cash quietly: through inventory creep, engineering sprawl, duplicated tooling, low yields, vendor sprawl, unused software, and over-spec'd infrastructure. Your job is to see those leaks before they become floods, and to build a culture of capital discipline without creating bureaucracy.

You report to the CFO and partner daily with engineering, operations, and supply chain. You will spend time on the manufacturing floor, not just in spreadsheets.

What You Will Own

Cash and capital efficiency

• Runway, burn multiple, and cash forecasting as live operating instruments — not quarterly artifacts
• Hard scrutiny on every recurring expense, vendor, contract, and headcount addition
• Aggressive negotiation with suppliers, landlords, contractors, and software vendors
• A defensible "no" when spending doesn't earn its keep — delivered without slowing the team

Hardware unit economics

• COGS, BOM, contribution margin, and yield economics down to the SKU and panel level
• Inventory turns, aging, scrap, and reagent usage as managed metrics, not reported ones
• Pricing strategy and margin discipline as the product scales
• Manufacturing ramp modeling: cost-down curves, learning rates, capacity vs. demand

Operational finance

• Embedded in engineering, ops, and supply chain — not adjacent to them
• Procurement gates on capital expenditure and tooling decisions
• SKU discipline, vendor concentration limits, and standardization wherever feasible
• Hiring efficiency: ROI per role, not just headcount plans

Systems and infrastructure

• A modern fintech stack (Ramp, Gusto, and beyond) wired into an ERP/MRP backbone
• Real-time financial visibility for leadership instead of month-end retrospectives
• Automation over headcount wherever a process can be codified

Reporting and dashboards that actually drive decisions

• Burn multiple, gross margin by panel, inventory aging, scrap and yield, reagent usage, vendor spend concentration, runway sensitivity, hiring efficiency, instrument payback
• Monthly leadership package and board materials that tell the operating truth, not the marketing story

What We're Looking For

Must have

• 7–10 years of progressive finance experience, with meaningful time at venture-backed hardware or manufacturing companies in the ~50–300 person range
• Demonstrated experience managing cash in a constrained environment — you've cut burn without breaking execution
• Deep cost accounting and hardware unit economics fluency (BOM, COGS, yield, contribution margin, inventory)
• Strong FP&A and operational finance — you build the model and own the operating cadence around it
• Comfortable challenging spending decisions across engineering and ops, with the credibility to make it stick
• Systems mindset: ERP/MRP, BOM management, procurement controls, inventory discipline
• Bachelor's in Finance or Accounting; advanced modeling skills assumed
• Authorization to work in the United States

Strong plus

• Biotech, life sciences, diagnostics, or medical device experience
• Hands-on with Ramp, Gusto, NetSuite or similar ERPs, and inventory/MRP systems
• Built or rebuilt a finance function during a manufacturing ramp or rapid hiring period
• History of walking the production floor and partnering with operators directly

Probably not the right fit if you

• Spent your career mainly preparing decks for fundraising rounds
• Come from big-pharma or big-tech finance only, without startup constraint experience
• Think finance is primarily backward-looking compliance and reporting
• Are too relationship-driven to challenge a senior engineer's purchase order
• Don't intuitively understand physical product economics

A Few Questions We'll Ask in the Interview

• Tell us about a time you materially reduced burn without hurting execution.
• What's the most wasteful spending pattern you see repeatedly in hardware startups?
• Walk us through the unit economics of a hardware product you've owned, end to end.
• Where would you start in your first 30 days here?

How We Work

Bias for action. We prototype, experiment, and iterate quickly. Extreme ownership. You own financial outcomes from forecast to close — and from PO to pallet. Talent density. We hire exceptional people who elevate the team around them.

Benefits

Competitive salary and significant equity, healthcare, dental, 401k, high-end gym membership, two company shutdown weeks each year on top of PTO, and the opportunity to help build a category-defining diagnostics company.

mike @ siphox.com far, please email mike @ siphox.com to be considered.