Running a full developer environment inside the browser
A web-based workspace that virtualizes a real runtime in the browser — code, run, and preview projects with no local setup.
The challenge
The product's promise was a zero-install coding environment — open a link and start building. That meant running an isolated, multi-window runtime in the browser, fast enough to feel native and safe enough to run untrusted code.
Our approach
We built a thin virtualization layer over the browser's own capabilities instead of shipping a heavy host VM. Each workspace boots a sandboxed runtime with its own filesystem, and a containerized backend handles anything that has to run server-side — keeping the client light and the platform secure.
What we built
- In-browser POSIX-style sandbox with a virtual filesystem
- Multi-window, responsive runtime that boots in well under a second
- Containerized backend for secure server-side execution
- Per-user projects with persistent storage and sharing
- Agent + tool loop for AI-assisted editing inside the workspace
The results
- Near-native responsiveness with minimal CPU overhead
- Workspaces boot in ~80ms with no local installation
- Untrusted code runs safely in isolated sandboxes
- Foundation reused to add AI coding assistance on top
"They turned a genuinely hard systems problem — a real dev environment in the browser — into something that just works."