Series A AI companies in San Francisco

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

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

1
Redrob· San Francisco, California, United States
Redrob - 'border' in reverse - is building LLMs for the next 3 billion. Purpose-built for sales, recruitment, and jobs. Series A funded with $14M. Backed by world-class VCs.
- Series A
- 218 employees
- Founded 2018
2
Xaira Therapeutics· South San Francisco, California, United States
Xaira Therapeutics is an integrated biotechnology company driving advances in artificial intelligence to learn the language of life and transform how we treat disease. We seek to rethink the drug discovery and development process from end-to-end by bringing together leading talent across three core areas: machine learning research to better understand biology, expansive data generation to power new models, and robust therapeutic product development to treat disease. Xaira is headquartered in the San Francisco Bay Area.Please be advised that we will never ask for personal information or any financial commitment from a candidate as a pre-employment requirement. All legitimate Xaira communication regarding our recruitment processes comes from email addresses ending with @xaira.com or through recognized professional networks, such as LinkedIn. To avoid any potential fraudulent activity, please make sure to apply only through Xaira's official Careers page: https://www.xaira.com/work-with-us
- Series A
- 213 employees
- Founded 2023
3
BIOMAKERS· San Francisco, California, United States
BIOMAKERS is a global Precision Medicine Company that produces complex & advanced genomic data + RWE to make cancer patients live longer and transform oncology data-driven Drug Development globally. having built an unprecedented platform that enables Diagnosis, Treatment, Drug Development, Target discovery and AI for Cancer and Rare Diseases, having developed genomic products in the 4 Stages of the Biopharmaceutical chain and providing the largest LATAM genomic representation in the global Oncology Drug Development Landscape.BIOMAKERS provides extensive genomic and molecular Testing services for cancer & rare disease patients in +18 countries in Latin America.In just a few years BIOMAKERS has become the leading company in Precision Medicine in the region having built the largest and unique of its kind multinational Advanced Tumor Biobank and Cancer Dataset from LATAM, with HQ in USA and fully owned Sequencing Labs in Mexico, Brazil, and Argentina.
- Series A
- 79 employees
- Founded 2014
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4
NGM Biopharmaceuticals· South San Francisco, California, United States
NGM Bio is a biopharmaceutical company focused on discovering and developing novel, life-changing medicines for people whose health and lives have been disrupted by disease.
- Series A
- 73 employees
- Founded 2008
5
Addition Therapeutics· South San Francisco, California, United States
Addition Therapeutics is on a mission to fulfill the transformative promise of genomic medicine for people impacted by both chronic and rare diseases. Leveraging our breakthrough all-RNA, non-viral, LNP-based PRINTTM platform, we are overcoming the limitations of existing genetic medicine modalities to develop safer, durable, one-time therapies. Bolstered by our team of top-tier scientists and engineers, we are advancing a robust pipeline of PRINTed therapeutics that have the potential to fundamentally redefine how chronic and rare diseases are treated. Our investor syndicate includes SR One, Pivotal Life Sciences, Abingworth, Osage University Partners, the Gates Foundation, and BEVC.
- Series A
- 68 employees

6
OneSkin· San Francisco, California, United States
Founded by female PhD scientists, OneSkin spent 10+ years researching skin aging and cellular senescence—leading to the OS-01 PeptideTM, our proprietary peptide engineered to reverse skin’s biological age and support healthier skin for the long-term.
- Series A
- 64 employees
- Founded 2016
7
Until· San Francisco, California, United States
We are building reversible cryopreservation technology to solve the organ procurement and matching problem.Cryopreservation is already essential to modern medicine — powering IVF and life-saving stem cell therapies. Now, we’re extending this technology to whole human organs — transforming hours of viability into weeks, or months, however long is necessary — so that no donated organ is lost to logistics, and no patient dies waiting. By solving this immediate need, we de-risk and build the foundation for what comes next: whole-body reversible cryopreservation. We're pausing molecular motion to give patients a bridge to future cures.
- Series A
- 63 employees
- Founded 2021
8
LatchBio· San Francisco, California, United States
Agent infrastructure for biology. Bundled with kits + machines to serve 300+ pharma, biotech and academic teams around the world.
- Series A
- 61 employees
- Founded 2021
9
Braveheart Bio· San Francisco Bay Area
Braveheart Bio is a clinical-stage biopharmaceutical company focused on developing therapies for patients with hypertrophic cardiomyopathy (HCM) and other serious cardiovascular diseases. Its lead product candidate, BHB-1893, is a next-generation oral small-molecule cardiac myosin inhibitor (CMI) being developed for the treatment of obstructive HCM (oHCM) and non-obstructive HCM (nHCM). Braveheart’s goal is to improve the treatment options for these patients by enhancing speed of onset, depth of gradient response, systolic safety, reversibility and reducing prescribing complexity.
- Series A
- 52 employees
- Founded 2025
10
Rime· San Francisco, California, United States
At Rime, we're on a mission to make voice AI feel more human.We bring deep linguistic and machine learning expertise to the problem of bridging the gap between humans and machines.Our technology is designed to bring warmth, authenticity, and emotional nuance to digital interactions, making conversations with machines feel more like conversations with real people.And our voices drive real results, like 15%+ call success, 23%+ increased sales, and 25%+ IVR containment for high growth startups and fortune 500 brands.
- Series A
- 51 employees
- Founded 2021

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Find engineers at Series A AI companies in San Francisco

Searching for “engineers at top Series A 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 A, by current headcount, drawn from public LinkedIn and Crunchbase records. With 49 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 A, 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 Series A 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: Thu, 15 Oct 2026 18:53:17 GMT

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