Founding Engineer

ThirdLayer is revolutionizing browser interaction by creating Dex, an intelligent AI copilot that seamlessly integrates with your browsing experience. As a Founding Engineer, you'll be at the forefront of developing next-generation browser-native AI technology.

The role involves building core infrastructure components including memory stores, context compression systems, and inter-agent protocols. You'll be working on high-performance state management, real-time UI observation systems, and creating scalable infrastructure for browser-native AI.

Key projects include:

• Developing systems to translate browser inputs (voice, keyboard, mouse, tab changes, DOM) into actionable workflow graphs
• Building agentic systems that can predict and execute users' next steps in complex workflows
• Creating searchable, self-updating memory stores for personalized user flow paths

The ideal candidate will be an expert in React/Next.js, TypeScript, and Python, with deep browser internals experience. You should have a proven track record of taking rapid prototypes to production. Prior experience with AI/ML infrastructure or agentic systems is preferred.

You'll be joining a small, fast-moving team backed by significant investment (7-figure) from top-tier investors. The company is tackling one of computing's most fundamental challenges: improving human-computer interaction through intelligent, context-aware systems.

This is an opportunity to shape the future of browser interaction and build technology that fundamentally changes how people interact with their computers. You'll be working directly with founding team members and have significant influence over the technical direction of the product.

The role offers competitive compensation ($130K - $250K) with meaningful equity (0.50% - 2.00%), reflecting the founding nature of the position. Based in San Francisco, you'll be part of a team focused on solving complex technical challenges while building products that directly impact user productivity and workflow efficiency.