# Summer 2026 Full-Stack Engineer Intern

**Company:** [Thirdlayer](https://zerogtalent.com/ai-companies/thirdlayer)
**Location:** San Francisco, CA, US
**Work mode:** On-site
**Seniority:** Intern
**Employment type:** Internship
**Salary:** USD 6000–10000/mo
**Category:** Software
**Listed:** 2026-11-09

[View and apply on Zero G Talent](https://zerogtalent.com/ai-jobs/thirdlayer/summer-2026-full-stack-engineer-intern-80751)

## What you'll do

- Build full-stack browser extension interfaces from research prototypes.
- Develop end-to-end features using React/Next.js, Python, and SQL.
- Design intuitive interfaces for delegating and overriding AI actions.
- Integrate iMessage, communications channels, desktop-native, and wearables platforms.

## What you need

- Strong foundation in React/Next.js and TypeScript.
- Experience building and shipping complex web apps and browser extensions.
- Familiarity with design systems like Figma.
- Proof of meaningful open-source contribution.
- Strong UI/UX or design portfolio.

## Job description

### **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.

## Other open roles at Thirdlayer

- [2026 Summer AI/ML Engineer Intern](https://zerogtalent.com/ai-jobs/thirdlayer/2026-summer-ai-ml-engineer-intern-80750) — San Francisco, CA, US
- [AI Engineer Intern](https://zerogtalent.com/ai-jobs/thirdlayer/ai-engineer-intern-76658) — San Francisco, CA, US
- [Full-Stack Engineer Intern](https://zerogtalent.com/ai-jobs/thirdlayer/full-stack-engineer-intern-76659) — San Francisco, CA, US
- [Founding Engineer](https://zerogtalent.com/ai-jobs/thirdlayer/founding-engineer-76656) — San Francisco, CA, US

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*Source: [Zero G Talent](https://zerogtalent.com), the job board for space, defense, AI, robotics and frontier-tech companies.*