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Building Dex, the AI Browser Copilot

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.
Active Founders
Regina Lin
Regina Lin
Founder
Regina is the co-founder & CEO of Dex. She studied Mathematics with a concurrent master's in Computational Science at Harvard (dropped out). She previously co-founded Contour AI, a devOps tool for LLM evaluation, helped build the MVP an ecommerce marketplace with 40K+ customers and worked in various tech investment roles.
Kevin Gu
Kevin Gu
Founder
Co-founder of Dex. Prev Math & Stat at Harvard, quant/ML researcher at Jump Trading, IBM Research, QuantCo, Meta.
Company Launches
Dex – Your AI Coworker for the Browser
See original launch post

Hey! We’re Kevin and Regina from Dexterity. Today, we’re launching Dex—the fastest interface for co-working with AI, right inside your browser.

TLDR: AI that works with you, not just for you. 10x your workflows without breaking your flow. Try Dex (Beta) → getdexterity.com

Why We’re Building This

Four weeks before Demo Day, we pivoted to build for ourselves.

Most AI web agents today are “set-and-forget” chats—you hand them off and check back later. But what about workflows you actually want to drive? Navigating platforms, moving data, making quick decisions—these moments demand instant, context-aware models that work with you, not just for you.

Imagine using Operator to order DoorDash—a frustratingly back-and-forth relay with no real-time visibility. That same friction exists for work tools like Jira, GSuite, and GitHub, where users need instant feedback and responsive action, not slow AI handoffs.

That’s why we’re taking a Cursor (vs. Devin) approach—for the browser.

The Problem

Modern work is a juggling act of 15+ tabs, software bloat, and constant UI friction, just to complete a single task.

The real bottleneck isn’t just automation—it’s context switching. Traditional solutions force users to memorize shortcuts (appeals to devs, but leaves everyone else behind), while AI tools make you adapt to them instead of living right where you work.

Why not turn your browser itself into an intelligent personal workspace?

How It Works

With simple voice and text, Dex enhances familiar interfaces, automates mundane actions, and understands your intent.

  • Smart Navigation🔸Find, execute, and move between apps.
  • Suggest Context🔸Cut down tab-switching and manual searching.
  • Cross-App Automation🔸Shortcut multi-step workflows, zero setup.
  • Adaptive UI/UX🔸Reshape, replicate, and browse by your rules.

Think of it like Spotlight Search meets AI automation + personal expert for everyday apps.

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Use Cases

  • GSuite – Write emails, find docs, and move data anywhere.
  • GitHub – Search repos, manage issues, and navigate faster.
  • Omni AI – Talk to and reference live tabs or integrated apps.

Coming Soon…

  • Meetings 📅 → Create and join calendar and Zoom events instantly
  • Sales 💼 → Automate clicks across LinkedIn, Sheets, and Apollo.io
  • Snippets ✂️ → Dex captures notes, links, and frequent snippets
  • Food 🍔 → Speak to browse options and order DoorDash

Our Ask

We’re building Dex for power users, founders, students, and curious explorers—because that’s who we are.

Join our waitlistGet notified when Dex goes live on the Chrome store.
Follow us on Twitter → Stay updated on latest features.
Discord → Get to know us more personally + brainstorm cool ideas.

Drop dream features to regina@getdexterity.com and let us know what you think!

Jobs at ThirdLayer
San Francisco, CA, US
$6K - $10K / monthly
Any
San Francisco, CA, US
$30 - $60
Any (new grads ok)
San Francisco, CA, US
$5.2K - $10.4K / monthly
Any
San Francisco, CA, US
$6K - $10K / monthly
Any
San Francisco, CA, US
$130K - $250K
0.50% - 2.00%
Any (new grads ok)
ThirdLayer
Founded:2025
Batch:Winter 2025
Team Size:2
Status:
Active
Location:San Francisco