Summer 2026 Full-Stack Engineer Intern

About the role

Full-Stack Engineer Intern

We're looking for engineers who can turn research prototypes into production-ready systems. You'll work at the intersection of browser automation, agent infrastructure, and intuitive UX that make complex agent behavior understandable and controllable.

Preferred: History of high-achieving projects/work experience, open source contributions, or competitive math/cs/physics experience.

What You'll Do

- Full-stack browser extension interfaces based on research prototypes.

- End-to-end features using React/Next.js, Python, and SQL.

- Design intuitive interfaces for how users should delegate and override AI actions.

- iMessage, communications channels, desktop-native, wearables integrations

Requirements

- Strong foundation in React/Next.js and TypeScript.

- Experience building and shipping complex web apps and/or browser extensions.

- Familiarity with design systems like Figma

- Preferred: Proof of meaningful open-source contribution.

- Preferred: Strong UI/UX or design portfolio.

Sample Projects

- Reusable tool call and output components for LLM-generated responses.

- Building efficient indexing, search, and memory layer architecture.

- Developing security and guardrails to approve and deny agent requests.

- Integrating third-party platforms (e.g. Slack, Notion, Gmail) to enable workflows.

See the posting on Thirdlayer's site