Refolk
BlogSign in

Y Combinator AI portfolio in San Francisco

The most prolific seed accelerator in the world, batch class twice a year. Filtered to AI companies headquartered in San Francisco.

Built from a search like: “Y Combinator-backed AI companies in San Francisco”

Ranked by current headcount across Y Combinator-backed AI companies in San Francisco. Refreshed daily.

  1. 1
    Culture Biosciences· South San Francisco, California, United States
    • Series C
    • 79 employees
    • Founded 2016
  2. 2
    ZBiotics· San Francisco, California, United States
    • Secondary
    • 58 employees
    • Founded 2016
  3. 3
    Miracle· San Francisco, California, United States
    • Pre-seed
    • 56 employees
    • Founded 2022
  4. 4
    Invert· San Francisco, California, United States
    • Seed
    • 47 employees
    • Founded 2021
  5. 5
    Elpha· San Francisco, Minnesota, United States
    • Seed
    • 43 employees
    • Founded 2019
  6. 6
    Cactus (YC S25)· San Francisco, California, United States
    • Pre-seed
    • 31 employees
    • Founded 2025
  7. 7
    Shasqi· San Francisco, California, United States
    • Grant
    • 29 employees
    • Founded 2015
  8. 8
    Verge Genomics· South San Francisco, California, United States
    • Series unknown
    • 28 employees
    • Founded 2015
  9. 9
    Probably Genetic· San Francisco, California, United States
    • Series unknown
    • 24 employees
    • Founded 2019
  10. 10
    Atomwise· San Francisco, California, United States
    • Series D
    • 18 employees
    • Founded 2012
  11. 11
    Menten AI· San Francisco, California, United States
    • Seed
    • 18 employees
    • Founded 2020
  12. 12
    Asher Biotherapeutics· South San Francisco, California, United States
    • Series C
    • 17 employees
    • Founded 2019
  13. 13
    Guide Labs· San Francisco, California, United States
    • Seed
    • 16 employees
    • Founded 2023
  14. 14
    Algen Biotechnologies· San Francisco, California, United States
    • Seed
    • 16 employees
    • Founded 2018
  15. 15
    Artos AI· San Francisco, California, United States
    • Pre-seed
    • 12 employees
    • Founded 2023
  16. 16
    Kopra Bio· San Francisco, California, United States
    • Pre-seed
    • 12 employees
    • Founded 2024
  17. 17
    d_model· San Francisco, California, United States
    • Seed
    • 12 employees
    • Founded 2024
  18. 18
    Ndea· San Francisco, California, United States
    • Seed
    • 11 employees
    • Founded 2024
  19. 19
    Metis· San Francisco, California, United States
    • Pre-seed
    • 11 employees
    • Founded 2025
  20. 20
    Anthrogen· San Francisco, California, United States
    • Seed
    • 10 employees
    • Founded 2024
  21. 21
    Orbillion Bio [Acquired]· San Francisco, California, United States
    • Series unknown
    • 9 employees
    • Founded 2019
  22. 22
    Olio Labs· San Francisco Bay Area
    • Seed
    • 9 employees
    • Founded 2023
  23. 23
    Alixia· San Francisco, California, United States
    • Seed
    • 6 employees
    • Founded 2022
  24. 24
    Equator Therapeutics· San Francisco, California, United States
    • Series unknown
    • 6 employees
    • Founded 2020
  25. 25
    ParcelBio· San Francisco, California, United States
    • Series unknown
    • 6 employees
    • Founded 2024

Y Combinator-backed AI companies in San Francisco

The list above ranks Y Combinator-backed AI companies headquartered in San Francisco by current headcount, drawn from public LinkedIn and Crunchbase records. With 39 matching companies in our index, you can see exactly where Y Combinator’s AI thesis has landed in San Francisco.

Three filters — investor, industry, city — narrow the field to a tight cluster of operators with overlapping incentives. They share a thesis, a network, and a market. Hiring from this list usually means hiring someone already inside the Y Combinator AI world in San Francisco.

Refolk converts this list into a live search. Ask for “Y Combinator AI companies in San Franciscohiring senior engineers” or “founders of Y Combinator-backed AI companies in San Francisco who left in the last year” and Refolk returns a ranked shortlist.

How this list is built

Refolk pulled AI companies headquartered in San Francisco whose disclosed Crunchbase investor list includes Y Combinator, ranked them by current employee count, and kept those with at least 3 employees. The list refreshes once a day.

Last refreshed: Thu, 07 May 2026 03:59:56 GMT

Need an even more specific search?

Refolk runs natural-language searches across LinkedIn, GitHub, and the open web. Try one of these:

Related lists

See all company lists.

Slice this list a different way