Founding Full Stack Engineer
Founding Full Stack Engineer at OpenBuilder — San Francisco, CA, US
- Company: OpenBuilder
- Location: San Francisco, CA, US
- Employment type: FULL_TIME
- Salary: USD 170000–220000 / year
- Posted: 2026-07-17
About this role
The Company
We’re building a web-based AI app builder that lets non-technical users create, modify, and deploy real applications. At the core of the product is a browser-based IDE, powered by VS Code Web, where AI collaborates with users to write, edit, and evolve code safely.
We believe AI should feel like a partner, not a black box. That means building systems that generate understandable changes, apply them predictably, and keep users in control.
The Role
We’re hiring a Founding Full-Stack Engineer to help build the heart of the product: the AI-powered app builder and IDE experience.
This is a senior / staff-level founding role with broad scope and real product ownership. You’ll work directly with the founders to define how AI interacts with code, how changes are reviewed and applied, and how non-technical users successfully build real software.
What You’ll Build
A browser-based IDE using VS Code Web
Custom VS Code extensions that enable AI-native workflows
AI systems that:
Generate code changes as explicit diffs
Apply patches safely and deterministically
Recover gracefully when models make mistakes
Interfaces that make code changes understandable to non-technical users
Tight feedback loops between user intent, AI output, and running applications
AI & Code Intelligence
AI is core to the product—not a feature bolted on later.
You’ll work on:
LLM-driven code generation, editing, and refactoring workflows
Supporting both hosted APIs and open-source models
Prompt design, evaluation, and iteration on real user tasks
Code diffing, patch application, conflict resolution, and validation
Guardrails that keep generated code safe, consistent, and debuggable
Systems that connect AI output directly to live, running applications
Integration with third-party APIs using MCP, allowing models to:
Discover available tools and services
Call external APIs in a structured, auditable way
Generate and apply code that correctly wires external services into user apps
Tech Stack
TypeScript, React
VS Code Web
VS Code Extensions (extension API, language services)
Django
PostgreSQL
LLMs: hosted models + open-source models
Infra: Fly.io (VMs), Google Cloud Platform
Edge & Networking: Cloudflare, Nginx
What We’re Looking For
3+ years of experience as a software engineer
Strong TypeScript and frontend engineering skills
Experience building complex web applications or developer tools
Familiarity with IDEs, editors, or VS Code extensions
Hands-on experience working with LLMs or AI-powered systems
Strong understanding of code structure, diffs, and refactoring workflows
Product-oriented mindset for non-technical users
Comfort shaping systems from scratch in an early-stage environment
Clear communicator who enjoys working closely with founders
Nice to Have
Experience building IDEs, compilers, or language tooling
Deep familiarity with VS Code internals or Monaco
Experience with open-source LLMs and inference pipelines
Backend experience (Django or similar)
Previous founding or early-stage startup experience
Why Join
Founding engineer role with real ownership and influence
Build an AI-native IDE from the ground up
Work on hard problems at the intersection of AI, tooling, and UX
Direct impact on how non-technical users create software
Close collaboration with founders
Competitive salary + meaningful equity