Seed AI companies in San Francisco

Companies building AI products, foundation models, and applied ML platforms. Filtered to Seed-stage companies headquartered in San Francisco.

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Ranked by current headcount across Seed AI companies in San Francisco. Refreshed daily.

1
Liquid Trees· San Francisco, California, United States
Say hello to Diatoms.Microscopic plants called Diatoms absorb 10-20 billion tonnes of carbon dioxide (CO2) every year. That's equal to the amount of carbon captured annually by all of the world's rainforests.Diatoms are considered the largest primary producers of oxygen on our planet. It is estimated that through photosynthesis, diatoms produce between 20% and 40% of the oxygen we breathe.With the campaign "Keeping the Planet cool with Diatoms" we are trying to raise awareness about Diatom potential in CO2 removal.We are in the process of removing 10GtCO2 by accelerating the growth of native diatoms in polluted open water systems.
- Seed
- 1.4k employees
- Founded 2022
2
Calico Life Sciences· South San Francisco, California, United States
Calico is an Alphabet-founded research and development company whose mission is to harness advanced technologies and model systems to increase our understanding of the biology that controls human aging. We will use that knowledge to devise interventions that enable people to lead longer and healthier lives. Calico’s highly innovative technology labs, its commitment to curiosity-driven discovery science and, with academic and industry partners, its vibrant drug-development pipeline together create an inspiring and exciting place to catalyze and enable medical breakthroughs.Calico is currently seeking exceptional candidates who share our passion for understanding the science of aging and developing therapeutics to address age-related diseases.Explore with us! https://www.calicolabs.com/careers
- Seed
- 492 employees
- Founded 2013
3
OPTIC· San Francisco, California, United States
AI-powered drug discovery platform for rapid molecule screening and testing, from target identification to lab validation. Automating biotech R&D.About Optic Optic started as an AI research team developing high-performance similarity search algorithms. Today our proprietary AI-technology is powering products in multiple industries from blockchain to biotech.
- Seed
- 283 employees
- Founded 2021
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4
Athena Alliance· San Francisco, California, United States
The Athena Alliance is a community that propels leaders to build impact, whether it’s in the C-suite, in the boardroom, as an investor, as an entrepreneur, as a thought leader and beyond. Since its founding, Athena has:• Built and nurtured a network of 3-,000+ C-level women, VCs, and CEOs from across the full range of industries.• Made thousands of connections between female executives and investment firms, CEOs, and boards.• Supported over 500 women to corporate board roles across the range of public, PE backed, VC backed, ESOPs and more.• Produced hundreds of hours of business leadership content on the most pressing topics - from governing to investing to building. • Offered over 250 virtual events and 80 live in person events EVERY YEAR across the US.• Launched Athena Academy with world class courses and faculty.Through the integration of community, content, and coaching, Athena supports women leaders to reach their most ambitious goals and think bigger.
- Seed
- 234 employees
- Founded 2021
5
Plasmidsaurus· South San Francisco, California, United States
We sequence whole plasmids, transcriptomes, amplicons, whole genomes, AAV, microbiomes, and colonies overnight, without the need for primers and minipreps.Plasmidsaurus is on a mission to accelerate new cures and promote a healthier planet by unlocking new levels of productivity for scientists. The company's sequencing services are used daily by thousands of innovators, including Nobel Prize winners, dynamic biotech startups, pharmaceutical companies, research labs, and DIY biohackers and have been cited in more than 2500 publications to date. Plasmidsaurus's global network of labs operates day and night to enable world-changing discoveries.Start sequencing: plasmidsaurus.com
- Seed
- 139 employees

6
Miracle· San Francisco, California, United States
Pulling your hair out in clinical trials because of spreadsheet madness?You’re not alone. Most biotech teams lose weeks, if not months, to manual spreadsheet trackers, delayed insights, and inadequate vendor oversight.That’s exactly why we built Miracle.👉 Speed: Replace clunky manual trackers with an integrated platform that gets you live in just days (not weeks or months).👉 Clarity: Real-time visibility across trials, so your execs stop asking you for “one quick update” every day.👉 Proof: Clinical-stage biotechs using Miracle have already finished 3-4 months ahead of trial timelines, freeing their teams from spreadsheet hell and resolving risks as soon as they occur, not next week.If you’re a biotech exec staring down another delayed trial (or want to start your study on the right foot), Miracle can help you close the gap.📩 Message us here or reach out at https://www.miracleml.com/contactLet’s make “trial delays” something you don’t talk about next quarter.
- Seed
- 73 employees
- Founded 2022
7
Orchid· San Francisco, California, United States
For the first time, parents have a new superpower. With Orchid, they can safely and naturally mitigate genetic risks in their future child. Sign up to get access at www.orchidhealth.com
- Seed
- 62 employees
- Founded 2020
8
Grand Time Research (Coordination Layer)· San Francisco, California, United States
Grand Time Research (Coordination Layer) represents a non-commercial, non-investment research coordination structure associated with the Grand Time architecture.This entity does not accept external investments, does not issue financial products, and does not operate as a registered fund.Its role is strictly limited to:– coordination of research and documentation efforts,– allocation of internal resources for development and verification,– stewardship of research records and contributor acknowledgments.Governance is non-voting and formula-constrained. Artificial intelligence, where referenced, is used strictly as a defensive and safety layer (e.g., anomaly and coercion detection), not as a governing authority.Non-goals:– no investment activity– no token sale– no promised financial returns– no governance voting– no production deployment
- Seed
- 61 employees
- Founded 2017
9
Subquadratic· San Francisco, California, United States
Subquadratic is a frontier AI research and infrastructure company building a new class of LLMs. We're pushing foundational change at the model architecture level, enabling large-context and multi-modal inference that scales efficiently where transformers can't.
- Seed
- 49 employees
- Founded 2025
10
Elpha· San Francisco, Minnesota, United States
Elpha (YC19) is the professional network dedicated to helping high-achieving women in tech succeed at work. Our 100,000+ members come to Elpha for support, to explore new opportunities, and to make friends. We're also a startup founded and built by women.If you'd like to get to know more women in your field, apply to become a member at elpha.com
- Seed
- 43 employees
- Founded 2019

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Find engineers at Seed AI companies in San Francisco

Searching for “engineers at top Seed AI companies in San Francisco” surfaces this slice of the market. The list above ranks AI companies headquartered in San Francisco whose latest disclosed round is Seed, by current headcount, drawn from public LinkedIn and Crunchbase records. With 85 matching companies in Refolk’s index, this is a tight read on where the AI talent in San Francisco is heating up.

Three filters at once narrows the field hard. The companies that survive all three - Seed, AI, in San Francisco - are usually the most targeted recruiting pool a hiring manager can ask for. Senior engineers, founding designers, and product leads here are about to become AI’s next operators and angel investors.

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Refolk pulled AI companies headquartered in San Francisco whose latest disclosed funding round is Seed from public LinkedIn and Crunchbase records, ranked them by current employee count, and kept those with at least 3 employees. The list refreshes once a day.

Last refreshed: Wed, 05 Aug 2026 21:29:17 GMT

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