YCW25· AIThirdlayer
Continual learning for enterprise AI
Founders
- Regina LinFounder/CEO
- Kevin GuFounder
Same space
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Closest in what they build, same category.
Adjacent
Overlapping tags, a different niche.
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Outside YC
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About Thirdlayer
ThirdLayer is the learning and alignment layer for enterprise AI. We continuously ingest and structure messy organizational context, complex operational processes, and siloed, permission-sensitive data, then grade agents against the outcomes each company cares about. Every interaction becomes feedback that helps agents improve over time. Companies use ThirdLayer to power their internal agents or embed it into the AI products they’re building. We give agents the context, evaluations, and learning loops they need to stay aligned with each organization and deliver better outcomes with every run.
San Francisco, CA, USA
Thirdlayer: questions
Which YC batch was Thirdlayer in?
Thirdlayer was in Y Combinator's Winter 2025 batch (W25).
Is Thirdlayer still active?
Y Combinator lists Thirdlayer as active.
Who founded Thirdlayer?
Thirdlayer's founders, as listed on its YC page: Regina Lin (Founder/CEO), Kevin Gu (Founder).
Where is Thirdlayer based?
Thirdlayer lists San Francisco, CA, USA as its location on YC's directory.
Not affiliated with Y Combinator. From YC's public directory. Logos via logo.dev; trademarks belong to their owners.