ThirdBrain Labs
ThirdBrain Labs is in a16z speedrun SR006. Based in San Francisco, California, United States of America. Team of 2, founded in 2025.
Facts
- San Francisco, California, United States of America
- 2
- 2025
About ThirdBrain Labs
Summary
ThirdBrain Labs is a San Francisco-based AI infrastructure startup founded in 2025 that helps organizations build, own, and continuously refine domain-specific AI models. Rather than relying on general-purpose, closed AI APIs, teams can encode their proprietary knowledge directly into fine-tuned models they fully control. The platform handles the full post-training lifecycle—from capturing expert decisions in real time to deploying task-optimized models—without requiring large labeled datasets or extensive manual data-labeling pipelines. The result is a model portfolio that a team owns outright, including the weights and underlying data, and that improves continuously as new domain signals are captured in production.
Business model
ThirdBrain Labs appears to operate on a B2B service or platform model, likely charging for access to its end-to-end post-training infrastructure and the ongoing model improvement system. Pricing is probably usage- or contract-based, reflecting the computational and engineering resources required to train and deploy custom models on a per-team basis.
Go-to-market
ThirdBrain Labs appears to target technical teams at domain-specialist organizations—such as enterprises, research groups, or vertical-software companies—that have accumulated deep proprietary knowledge and want to translate it into AI capabilities without outsourcing to black-box model providers. The buying motion likely involves a consultative, demo-driven sales process, given the "Book a demo" call-to-action prominently featured on the site. Customer acquisition likely combines direct outreach to domain experts and researchers alongside word-of-mouth within specialized professional communities.
Founders (2)
- David Huang
- Margaret Zhang
Score a cohort against your own thesis
GPAgent's sourcing agent reads cohorts like this one and scores each company against your fund's mandate in a private workspace. Your scores, notes, and pipeline never appear on these pages.
Join the waitlist