---
title: 'Machine Learning Engineer / Scientist at Until'
canonical: 'https://feeny.ai/job/machine-learning-engineer-scientist-until-bay-area-36xaqmy28p8q'
type: 'job'
last_seen: '2026-09-07'
---

# Machine Learning Engineer / Scientist at Until

- **Company:** Until
- **Location:** Bay Area
- **Compensation:** $140k–$240k
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2025-11-25
- **Last confirmed live:** 2026-09-07
- **Apply:** https://jobs.lever.co/until/b953a7f9-3024-43c2-abed-45cf5a91ddd3

## Job description

Until is a moonshot company building a “pause button” for biology. Our near-term focus is organ-scale reversible cryopreservation: preserving donated organs at subzero temperatures without ice formation, then rewarming them uniformly for transplant. By solving this grand challenge, we’re laying the foundation for whole-body reversible cryopreservation, giving patients a bridge to future cures.

To achieve our goal, we are assembling an interdisciplinary team to develop perfusion systems, cryoprotectant formulations, and vitrification and rewarming hardware. We are also building out our medical hibernation team to tackle the challenges of whole-body cryopreservation, beginning with rodent models.

We envision a future where no transplantable organ is lost to logistics, and no terminal diagnosis is final because patients can safely wait for future medicine to arrive.

## About the Role

As a Machine Learning Engineer / Scientist at Until, you will be an early member of the computational team defining how experimental data becomes insight and drives the next round of scientific discovery. You’ll build high-leverage ML systems that help develop new cryoprotectant formulations, engineer biologically-inspired antifreeze proteins, and understand the physics of vitrification and rewarming. You will own projects end-to-end including shaping data collection and designing data pipelines, training and evaluating models, and deploying tooling that scientists use daily.

## About You

- Degree in Computer Science or a related field (Applied Mathematics, Statistics, Data Science, Computational Biology).
- Excellent foundations in the mathematics that underlies machine learning, including linear algebra, probability, statistics, and calculus.
- Strong experience in modern machine learning approaches, such as representation learning, generative modeling, active learning, and bayesian optimization.
- Track record of developing ML approaches for scientific discovery, as evidenced by a strong publication record, substantial open source contributions, or deployment of a machine learning system in an industry role.
- Demonstrated ability to write modular, maintainable, and performant code in Python.
- Fluency with the Python data science and ML stack, including PyTorch, NumPy, SciPy, Pandas/Polars, Matplotlib/Plotly.
- Proficient with developer tooling, including Linux command line, Git, and shell scripting.
- Ability to think from first principles and tackle complex, cross-disciplinary problems with other scientists and engineers.

## Preferred Qualifications

- 3+ years of relevant professional or research experience, or a PhD in a computational field.
- Strong understanding of computer science fundamentals, including algorithms, operating systems, and concurrency.
- Experience with cloud infrastructure (AWS, GCP) and SQL databases.

## Benefits

- Opportunity for outsized impact creating the future as an early team member
- Generous medical, dental and vision insurance coverage
- Flexible time off and paid holidays
- Competitive compensation package, including salary and equity
- 401(k) retirement savings plan
- FSA and commuter benefits
- Subsidized lunch daily

## About Until

## Company Overview
- **One-liner**: Until is building reversible cryopreservation technology to bank whole human organs, extending viability from hours to weeks or months, with the long-term goal of whole-body cryopreservation.
- **Entity Type**: Private (Privately Held)
- **Headquarters**: San Francisco, California, United States
- **Founded**: 2025
- **Founders**: Laura Deming (CEO, Co-founder) and Hunter Davis Ozawa (CSO, Co-founder)

## Core Business
- Primary industry/industries: Biotechnology Research, Cryopreservation, Organ Preservation, Hibernation Science
- Target customers: Organ procurement organizations, transplant hospitals, and ultimately patients waiting for organ transplants (B2B with healthcare institutions)
- Mission or purpose statement: "Pressing pause on biological time, for those who need it most." The company aims to solve the organ procurement and matching problem by making donated organs last long enough to reach any patient in need.

## Products & Services
- **Reversible Cryopreservation for Whole Organs**: A technology that cools organs to -130°C using biocompatible cryoprotectants, then rewarms them without damage, turning hours of viability into weeks or months.
- **Cryoprotectant Discovery Engine**: A platform combining physics simulations and machine learning to screen over 250,000 candidate molecules for cryoprotective formulations that stay within a "Biocompatibility Budget" – preventing ice formation without harming cells.
- **Hibernation Research**: Exploratory work on inducing reversible metabolic arrest (hibernation-like states) in organisms, with potential applications in organ preservation and future whole-body suspension.

## Market Standing
- **Valuation/Market Cap**: Not publicly available (private company, founded 2025)
- **Key Metric**: Total Funding – Not disclosed; headcount of 53 employees (as of early 2026) with 9.5% monthly growth and 29 active job postings.
- **Notable Investors/Partners**: Not publicly listed. The company is co-founded by Laura Deming, a noted longevity and biotech investor (founder of the Longevity Fund), which may signal strong investor connections.
- **Growth Signals**: Rapid hiring (29 open roles for a 53-person team, +31.8% quarterly job posting growth), high-throughput screening scale (2,903 formulations tested in Q2 2026 alone), and public progress on cryoprotectant discovery.

## Competitive Advantages
- **Combination of Physics Simulation and ML**: Their discovery engine screens millions of molecules in silico before wet-lab validation, dramatically accelerating cryoprotectant development.
- **Biocompatibility Budget Framework**: A novel approach that distributes cryoprotectant toxicity across multiple mechanisms, avoiding the single-dose toxicity that has stymied the field for 50 years.
- **Focus on Whole Organs (not just cells)**: Extending cryopreservation from small samples (IVF, stem cells) to whole human organs – a much harder problem with massive clinical impact.
- **Talent Philosophy**: "Proof of work" culture that hires for demonstrated ability over credentials, with fast promotion for those who earn it.

## Strategic Focus
- **Immediate**: Scale up cryoprotectant discovery and validation to achieve reversible cryopreservation of a whole human organ (likely a kidney or heart) within the next few years.
- **Medium-term**: De-risk and build the foundation for whole-body reversible cryopreservation, enabling "a bridge to future cures" for patients with currently incurable conditions.
- **Talent Acquisition**: Aggressively hiring scientists, engineers, and operations staff across physics, biology, chemistry, and engineering disciplines to accelerate R&D.

## Why Work Here
- **Work Environment**: On-site in San Francisco (HQ). The work spans "the edge of physics, biology, and engineering" – from quantum-level simulations to handling real organs. Culture emphasizes "hard problems", rigor, and speed.
- **Culture**: Flat hierarchy, promotion on merit, "proof of work" over credentials. Team includes people from top universities and self-taught scientists alike.
- **Benefits**: Comprehensive medical/dental/vision, 401(k) via Guideline, unlimited PTO, paid parental and disability leave, on-site fitness center, catered lunch and dinner, plus snacks.
- **Engineering & Science**: Opportunity to work on cutting-edge cryobiology, nanotech, polymer chemistry, and high-throughput automation. The company uses AI tools in hiring but makes final human decisions.

## Sources
1. [untillabs.com/careers](https://www.untillabs.com/careers)
2. [untillabs.com](https://untillabs.com/)
3. [untillabs.com/our-team](https://www.untillabs.com/our-team)
4. [builtin.com/company/until-labs](https://builtin.com/company/until-labs)
5. [jobs.lever.co/until](https://jobs.lever.co/until)

## Other roles at Until

- [Electrical Engineer / Applied Physicist](https://feeny.ai/job/electrical-engineer-applied-physicist-until-bay-area-kgcsag1hxzzk) — Bay Area
- [Lab Manager](https://feeny.ai/job/lab-manager-until-bay-area-y2t4zfrgq8f2) — Bay Area
- [Mechanical Engineering, Design](https://feeny.ai/job/mechanical-engineering-design-until-bay-area-cbaa9hk1my9k) — Bay Area
- [Senior Scientist, Cardiac Preservation (Organ Perfusion)](https://feeny.ai/job/senior-scientist-cardiac-preservation-organ-perfusion-until-bay-area-b452rfthhqkp) — Bay Area
- [Research Associate (Organ Perfusion)](https://feeny.ai/job/research-associate-organ-perfusion-until-bay-area-0b1srem75ztf) — Bay Area
- [Research Assistant, Materials Chemistry (Nanoparticles)](https://feeny.ai/job/research-assistant-materials-chemistry-nanoparticles-until-bay-area-3m7hw2phjy84) — Bay Area
- [Scientist/ Senior Scientist - Translational Cardiac Biology](https://feeny.ai/job/scientist-senior-scientist-translational-cardiac-biology-until-bay-area-4t7rwnr11n7h) — Bay Area
- [Head of Legal](https://feeny.ai/job/head-of-legal-until-bay-area-a15h6wha3f21) — Bay Area
- [Research Associate, Hibernation](https://feeny.ai/job/research-associate-hibernation-until-bay-area-a9jr1rkbe83f) — Bay Area
- [Physics and Engineering Technician](https://feeny.ai/job/physics-and-engineering-technician-until-bay-area-csevrzjywfzk) — Bay Area