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Y Combinator portfolio in San Francisco

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

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

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

  1. 1
    Airbnb· San Francisco, California, United States
    • Post-IPO debt
    • 69.2k employees
    • Founded 2007
  2. 2
    Twitch· San Francisco, California, United States
    • Series C
    • 17.5k employees
    • Founded 2011
  3. 3
    Stripe· South San Francisco, California, United States
    • Secondary
    • 14.7k employees
    • Founded 2010
  4. 4
    Deel· San Francisco, California, United States
    • Series E
    • 9.1k employees
    • Founded 2019
  5. 5
    OpenAI· San Francisco, California, United States
    • Series unknown
    • 7.8k employees
    • Founded 2015
  6. 6
    Rippling· San Francisco, California, United States
    • Series G
    • 7.2k employees
    • Founded 2016
  7. 7
    Scale AI· San Francisco, California, United States
    • Corporate
    • 6.5k employees
    • Founded 2016
  8. 8
    Reddit, Inc.· San Francisco, California, United States
    • Series F
    • 4.7k employees
    • Founded 2005
  9. 9
    Gusto· San Francisco, California, United States
    • Series A
    • 4.4k employees
    • Founded 2011
  10. 10
    Clipboard· San Francisco, California, United States
    • Series C
    • 3.4k employees
    • Founded 2016
  11. 11
    GitLab· San Francisco, California, United States
    • Series E
    • 3.4k employees
    • Founded 2014
  12. 12
    Cambly Inc.· San Francisco, California, United States
    • Series A
    • 3k employees
    • Founded 2012
  13. 13
    Flexport· San Francisco, California, United States
    • Convertible note
    • 2.8k employees
    • Founded 2013
  14. 14
    Instawork· San Francisco, California, United States
    • Series D
    • 2.3k employees
    • Founded 2016
  15. 15
    Homebase· San Francisco, California, United States
    • Series D
    • 1.8k employees
    • Founded 2014
  16. 16
    Magic· San Francisco, California, United States
    • Series unknown
    • 1.8k employees
    • Founded 2014
  17. 17
    Brex· San Francisco, California, United States
    • Debt
    • 1.8k employees
    • Founded 2017
  18. 18
    Vanta· San Francisco, California, United States
    • Series D
    • 1.7k employees
    • Founded 2018
  19. 19
    Webflow· San Francisco, California, United States
    • Series unknown
    • 1.7k employees
    • Founded 2013
  20. 20
    Checkr, Inc.· San Francisco, California, United States
    • undisclosed
    • 1.7k employees
    • Founded 2014
  21. 21
    6sense· San Francisco, California, United States
    • Debt
    • 1.6k employees
    • Founded 2013
  22. 22
    Cruise· San Francisco, California, United States
    • Corporate
    • 1.6k employees
    • Founded 2013
  23. 23
    Faire· San Francisco, California, United States
    • Secondary
    • 1.5k employees
    • Founded 2017
  24. 24
    Zapier· San Francisco, California, United States
    • Series unknown
    • 1.4k employees
    • Founded 2011
  25. 25
    Forage· San Francisco, California, United States
    • Series B
    • 1.3k employees
    • Founded 2017

Y Combinator portfolio companies in San Francisco

Y Combinator’s San Francisco portfolio is one of the most active recruiting pools in the market. The list above ranks Y Combinator-backed companies headquartered in San Francisco by current headcount, drawn from public LinkedIn and Crunchbase records. With 1,103 matching companies in our index, you can see exactly where the Y Combinator thesis has landed locally.

Y Combinator companies in San Franciscotend to attract a specific type of operator — a founder or early hire bought into both the firm’s thesis and the city’s ecosystem. That makes the engineers and designers at these companies particularly valuable signals.

Refolk lets you reach this pool. Ask for Y Combinator companies in San Franciscohiring founding engineers” or “founders of Y Combinator-backed companies in San Francisco who left in the last year” and Refolk returns a ranked shortlist with evidence behind each match.

How this list is built

Refolk pulled companies whose disclosed Crunchbase investor list includes Y Combinator and whose HQ is in San Francisco, ranked them by current employee count, and kept those with at least 5 employees. The list refreshes once a day.

Last refreshed: Thu, 07 May 2026 07:45:33 GMT

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