Dex YC Application

Winter 2025Active

Dex went through Y Combinator in the Winter 2025 batch as a B2B company. Below: what the company does, who founded it, and its application to YC, reconstructed question by question in the real YC form.

YC batch: Winter 2025
Industry: B2BProductivity
Team size: 2
Status: Active
Launched: 2025

Founders

Regina LinFounder
Kevin GuFounder

What Dex does

ThirdLayer is an applied research and product lab building the next interface for human - AI collaboration. Our first product is Dex, an AI copilot for the browser. Think Cursor for knowledge work, optimized for speed and embedded directly where you work. Most web agents are built for set-and-forget tasks. But real work is fluid and messy - spread across tabs, tools, and evolving decisions. Dex transforms your browser into an intelligent, multimodal workspace that understands your intent through voice, text, and action. It enhances familiar interfaces, automates tedious steps, and removes the friction of handoffs. Beneath the surface, Dex is more than a browser agent - it’s a foundation for: ● Long-term, cross-modal memory grounded in real workflows ● A new interaction layer to replace static UI with a collaborative canvas ● Personalization: understanding how individuals approach tasks and navigate software We're building the infrastructure for adaptive, intent-aware systems that work the way you do.

Dex's YC application, reconstructed

Y Combinator application

Dex, Winter 2025 batch. The real form questions, answered from public data.

Founders2
Company7
Progress7
Idea4
Equity3
Curious2
Batch Preference1

Company

Company name

Dex

Describe what your company does in 50 characters or less.

The AI Coworker in Chrome

What is your company going to make? Please describe your product and what it does or will do.

We are building Dex, an AI copilot inside the browser that helps people work faster and more fluidly across tabs and tools. It understands inputs via voice, text, and actions, automates tedious steps, and builds a long-term memory of how users work to personalize and simplify knowledge work.

Where do you live now, and where would the company be based after YC?

We currently live in San Francisco. After YC, the company will remain based in San Francisco.

Explain your decision regarding location.

San Francisco is where we both live and where our users tend to be. It's also a hub for high-intensity knowledge work that uniquely needs our product.

21 more answers in the full application

Founders, Progress, Idea, Equity, Curious, Batch Preference are in the full version. Create a free account to open it in YC Insights, next to every other YC batch.

See full application

Frequently Asked Questions

Is this the real Dex YC application?

No. Y Combinator keeps submitted applications private. This is a reconstruction: the real YC form questions, answered from Dex's public data (launch notes, founder backgrounds, product description). It shows how a company like Dex would present itself to YC, not the text they submitted.