Fundraising Fox
/Companies
Sign in

Thirdlayer

YC W25

San Francisco, US · Founded 2025 · 2 employees · Hiring · 7 known investors

Find your way into Thirdlayer

Sign up to see every warm intro you have to Thirdlayer

  • Paths you didn't know you had: your email and LinkedIn already hold routes to the Thirdlayer team. We find them for you
  • 2nd- and 3rd-degree connections: the friend-of-a-friend routes that take hours to manually find through your inbox or LinkedIn
  • Answers now, not in days: momentum is everything in a raise. Skip asking around whether someone knows someone

Days of research, done the moment you sign in, with every route ranked by how warm it is.

Sign up with GoogleAlready have an account? Log in

Dex is an AI-powered workspace assistant that ingests operational data across a user's tools and integrations, organizing it into structured context and a knowledge base. It automates tasks, generates insights, and proactively maintains information while users work across their browser and connected applications.

Also known as Dex AI, Inc. · Dex · Dexterity · Dexterity AI · Dexterity, Dex, Dexterity AI, Dexterity, Dex, ThirdLayer, Dex · ThirdLayer

AI & Machine LearningEnterprise SoftwareFuture of WorkSaaSArtificial IntelligenceProductivityConsumer ProductsAIUnited States of AmericaAmerica / Canada

Founders & leadership· Y Combinator alumni (W25)

Thirdlayer was founded in 2025 by Regina Lin and Kevin Gu.

RLRegina Lin
Regina LinCEORegina Lin is CEO and co-founder of Dex. She studied mathematics and computational science at Harvard, and previously co-founded Contour AI, an LLM evaluation devOps platform, while also contributing to e-commerce marketplace development and working in technology investment roles.
KGKevin Gu
Kevin GuFounderKevin Gu is a co-founder of Dex. He studied mathematics and statistics at Harvard and has held quantitative and machine learning research roles at Jump Trading, IBM Research, QuantCo, and Meta.
CD
Christina DuongOperationsformer
ML
Martin LeeOperationsformer
HZ
Harley ZhangOperationsformer

Investors · 7

B37 Ventureslisted by B37 VenturesSan Francisco · $100K – $3M

How we know: B37 Ventures's portfolio page · Not right? Tell us

Y Combinatorlisted by Y CombinatorSan Francisco · $500K

How we know: the Y Combinator directory · Not right? Tell us

A16Z SpeedrunreportedSan Francisco · $1M

How we know: fortune.com · Not right? Tell us

Concept VenturesreportedLondon · $1.5M

How we know: funding news · fortune.com · Not right? Tell us

Notion CapitalreportedLondon · $1M – $100M

How we know: funding news · fortune.com · Not right? Tell us

Also in the syndicate · 1

Andreessen Horowitz's Speedrun programme

Funding

SEC filings, press & company announcements

$5.3M disclosed across 1 of 2 rounds · 2025–2026

Source: company announcements and press reports — follow each round's link for the claim.

Founder mafia

2 people who came through Thirdlayer went on to found or lead other companies.

Regina LinCEOFounded DexKevin GuFounderFounded Dex

Related companies · 10

DexDex is a relationship management tool that provides an intuitive, modern rolodex for organizing and maintaining personal and professional contacts. It eliminates manual data entry and tedious processes, designed as a lightweight alternative to spreadsheets and sales CRMs.
MailTimeMailTime reformats email threads into chat-style conversations and separates personal communications from marketing messages and newsletters.
DexDex is an AI-powered recruiting platform that matches software engineers with relevant job opportunities through curated role recommendations and direct access to hiring teams, eliminating traditional application processes. The platform leverages AI to provide candidate-company matching at scale for technology companies.
aSimA platform for creating and sharing mini-apps and games built by community developers, featuring AI-powered features like video generation and image scoring alongside casual gaming experiences.
stratifyStratify provides continuous user research and usability testing for UX teams, enabling scalable user interviews to validate designs and inform product decisions. The platform helps product and design teams gather feedback on prototypes, wireframes, and user flows throughout the design process.
MarkItMarkIt develops AI agents that integrate into trade compliance workflows to help suppliers, brokers, and manufacturers with tasks like product classification, customs audit preparation, and record management.
NexthinkNexthink is a software company that provides IT departments with real-time analytics, automations, and employee feedback tools to improve digital workplace experiences. Its platform serves enterprise IT teams managing digital employee experience.
ORO AIORO AI operates an open benchmark and evaluation platform for shopping agents, where developers submit agents that independent validators test against daily-changing tasks, with results feeding back as training data. It serves builders of agentic commerce systems.
CoingeckoCoinGecko is the world's largest independent cryptocurrency data aggregator, providing comprehensive market data including price, volume, and market capitalization across thousands of cryptoassets. It serves millions of users globally with tools, research, and APIs for cryptocurrency market analysis and insights.
DEX ImagingDEX Imaging is the nation's largest independent copier and imaging equipment dealer, providing sales and service solutions to businesses.

Companies working in the same space as Thirdlayer.

Legal entities · 1

corporate structure
Dex AI, Inc.

Frequently asked questions

What does Thirdlayer do?
Dex is an AI-powered workspace assistant that ingests operational data across a user's tools and integrations, organizing it into structured context and a knowledge base. It automates tasks, generates insights, and proactively maintains information while users work across their browser and connected applications.
Who founded Thirdlayer?
Thirdlayer was founded by Regina Lin, Kevin Gu in 2025.
Who are Thirdlayer's investors?
Thirdlayer's investors include Theory Ventures, B37 Ventures, Y Combinator, A16Z Speedrun, Concept Ventures, Notion Capital.
How much funding has Thirdlayer raised?
Thirdlayer has disclosed $5.3M raised across 1 of its 2 known rounds.
Where is Thirdlayer headquartered?
Thirdlayer is headquartered in San Francisco, US.