What they do:
Near-real-time video infrastructure for LLMs
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HQ: San Francisco, CA, United States
Top AI Infrastructure Startups in California
This list has 52 startups and was last updated on Oct 15, 2026. 13 of them are hiring right now. Largest teams: Rootly, Domu Technology Inc., and Middleware. Latest round: Thunder GPU raised $15.7M (Jun 16, 2026).
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What they do:
AI Brokers for Industrial Trade
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HQ: San Francisco, CA, United States
What they do:
The biggest crowdsourced benchmark for Computer-Use
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HQ: San Francisco, CA, United States
What they do:
Give AI agents the right context at the right moment
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HQ: San Francisco, CA, United States
What they do:
Interpretability and reasoning infra for foundation models.
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HQ: San Francisco, CA, United States
What they do:
The open source tool gateway
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HQ: San Francisco, CA, United States
What they do:
Reimagining how Machines Learn
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HQ: San Francisco, CA, United States
YC W25Early stage
What they do:
AI teammates for your business-critical work.
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HQ: San Francisco, CA, United States
YC S26Early stage
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HQ: San Francisco, CA, United States
Incorporated: 2024
Funding:
$15.7M · Equity · Jun 2026
Sepal AI
Acquired
What they do:
Data Development for Advanced AI
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HQ: San Francisco, CA, United States
Helicone
Acquired
What they do:
LLM Observability for Developers
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HQ: San Francisco, CA, United States
TensorPool
Acquired
What they do:
Vercel For GPUs
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HQ: San Francisco, CA, United States
DAGWorks Inc.
Acquired
What they do:
Open source tools & services for reliable AI Agents & AI Applications
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HQ: San Francisco, CA, United States
Neptune.io
Shut down
What they do:
A self-healing platform to enrich and fix server alerts automatically
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HQ: San Francisco, CA, United States
Airtrain AI
Shut down
What they do:
No-code data curation for LLM fine-tuning and evaluation.
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HQ: San Francisco, CA, United States
FloydHub
Shut down
What they do:
ML Platform for developing, training and deploying ML models
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HQ: San Francisco, CA, United States