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Series C AI companies in San Francisco

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

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Built from a search like: “Top Series C AI companies in San Francisco”

Ranked by current headcount across Series C AI companies in San Francisco. Refreshed monthly.

  1. 1
    Loyal· San Francisco, California, United States

    Loyal Animal Health, Inc. is a clinical-stage veterinary medicine company developing drugs intended to extend the lifespan and healthspan of dogs. In other words, our mission is to help dogs live longer, healthier lives.We’ve already achieved significant milestones on our path to gaining FDA approval for the first lifespan extension drug for any species. Our team includes scientists, veterinarians, engineers, operators, and creatives. Join us in our mission to help dogs everywhere.

    • Series C
    • 219 employees
    • Founded 2020
  2. 2
    Arsenal Biosciences, Inc.· South San Francisco, California, United States

    ArsenalBiosciences, Inc., is a clinical stage programmable cell therapy company focused on the realization of solid tumor cell therapy to defeat cancer. Our discovery engine comprises precise CRISPR-enabled genome editing, integrated circuits incorporating logic gates for improved tumor targeting, and therapeutic enhancements enabling multiple pharmaceutical functions. With our programmable and computationally driven approach, we aim for enhanced and broader efficacy, increased patient safety, reduced provider costs and expanded market access. Our team is engineering living medicines to attack cancer’s inherent multi-faceted nature and bring dramatic improvements to the lives of patients.

    • Series C
    • 166 employees
    • Founded 2019
  3. 3
    Frontier Medicines· South San Francisco, California, United States

    Frontier Medicines, located in South San Francisco, CA and Boston, MA, is a precision medicine company that has pioneered a powerful discovery and development platform designed to generate medicines against disease-causing proteins previously considered undruggable. We are deploying our technologies in chemoproteomics, covalent drug discovery, and machine learning to develop a pipeline of groundbreaking medicines against the most important drivers of disease. Our lead program targets both the activated and inactive forms of KRAS G12C, a validated driver in a number of cancers that until recently has been undruggable. Our pipeline embodies our vision of bolding advancing science to defeat disease, starting with cancer.

    • Series C
    • 80 employees
    • Founded 2018
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  5. 4
    Unlearn.AI· San Francisco, California, United States

    Unlearn exists to transform clinical development by making every trial smarter.

    • Series C
    • 74 employees
    • Founded 2017
  6. 5
    NewLimit· South San Francisco, California, United States

    NewLimit is a biotechnology company working to radically extend human healthspan. We’re developing medicines to treat age-related diseases by reprogramming the epigenome, a new therapeutic mechanism to restore regenerative potential in aged and diseased cells. We leverage functional genomics, pooled perturbation screening, and machine learning models to unravel the biology of epigenetic aging and disease using experiments of unprecedented scale.All correspondence from NewLimit will come from an @NewLimit.com email address.

    • Series C
    • 63 employees
    • Founded 2022

Find engineers at Series C AI companies in San Francisco

Searching for “engineers at top Series C 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 Series C, by current headcount, drawn from public LinkedIn and Crunchbase records. With 18 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 - Series C, 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.

Refolk converts this list into a live search. Ask for “senior engineers at Series C AI companies in San Francisco hiring” or “founders of Series C AI companies in San Francisco who left in the last year” and Refolk returns a ranked shortlist with the evidence behind each match.

How this list is built

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

Last refreshed: Tue, 20 Oct 2026 17:01:02 GMT

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How is this ranking built?

The list draws on the public company graph - headcount and growth signals, funding history, and recency. The criteria chips at the top show exactly which filters produced it, and the methodology section explains the ranking.

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