← Back to roles

Founding Engineer

San Francisco•Full-time•$150k-220k/yr

We're creating the third layer for AI agents that live in your browser. If that excites you, and you're a world-class infrastructure expert, please apply.

Why you'll love ThirdLayer

  • Competitive Pay: We match top-tier salaries and bonuses.
  • Meaningful Equity: Be a co-owner in a 7-figure-backed startup.
  • Hacker House: Work and live full-time out of our 3-story SF loft.
  • Unlimited Scope: Work directly with founders to shape the product.

What You'll Build

  • Core agent components, including memory stores, context compression, inter-agent protocols, planning and tool use.
  • High performance state management and real-time UI observation systems.
  • Scalable infrastructure for browser-native AI.

Requirements

  • Expert in React/Next.js, TypeScript, and Python.
  • Deep browser internals experience.
  • Proven rapid prototype to production track record.
  • Preferred: Prior experience with AI/ML infra or agentic systems.

Sample Projects

  • Translating browser inputs (voice, keyboard and mouse inputs, tab changes, DOM) into actionable workflow graphs.
  • Agentic systems that predict and execute users' next steps in complex workflows.
  • A searchable, self-updating memory store for personalized browser agent behaviour.